Nutrients

 Nutrients are very important; without proper nutrients, we would not function properly.

The common nutrients are:
Carbohydrates, Lipids and Proteins.
Vitamins and Mineral ions.
Fibres and Water.

Nutrients are gathered from the foods that we eat, let's start off with the most common ones carbohydrates, lipids and proteins, these come from our pasta, potatoes and breads, these carbohydrates are often very starchy, these carbohydrates give us energy which is used for us to move around and conduct chemical reactions in our bodies.

Next are Lipids, which are the other name for 'fats', found in fatty foods and oils. These fats are commonly found in seeds, dairy products, and types of oily fish. The difference between these liquids and oils is that oils are liquid at room temperature, but fats are solid. 

They also provide energy to our bodies, but compared to carbohydrates, this energy source is more long-term since fat can be stored for longer compared to carbohydrates. Fats are also inside our bodies, with it being a layer of fat to keep us warm under our skin, and they also keep our organs safe.

Proteins are commonly found in seeds, fish and meats, and legumes like beans and lentils. These proteins are needed for growth and repairing damaged tissues, but the amount of energy that they can provide is much less compared to lipids or carbohydrates. If we don't have enough of either, the proteins can suffice.

Vitamins and Minerals are different as vitamins are from living organisms like while minerals are from inorganic sources, like iron, which is needed much less compared to vitamins.
Vitamin A are gathered from eating leafy vegetables and livers, other vitamins like vitamin C from oranges or other citrus fruits are meant to stop you from getting scurvy, which happens when you don't have enough vitamin C and can cause your gums to bleed. 
Vitamin D is gathered from standing in the sun, as, strangely enough, the body makes vitamin D from sunlight, which is the best way to get it.
Other sources, via eggs and oily fish, the purpose of vitamin D is that it helps your body absorb Calcium.

This is a good segue to what Calcium is, which is a mineral, and is commonly found in milk and leafy veggies. If you don't have enough Calcium, then your bones will deform from a disease named Rickets.
Last is iron. If you have done the experiment where you crush up cereal, you will find small magnetic chunks of iron in the cereal, which our bodies need for helping red blood cells transport oxygen throughout the body.
If you don't have enough iron, then you might get Anemia, which is when the body can't transport enough oxygen to your tissues, and is a vital part of haemoglobin. This is found in foods like red meats, beans and spinach.

Lastly is Fibre and Water are also nutrients with their own purposes. Fibre is considered to be a type of carbohydrate, but the key difference is that we don't absorb it into the body, its purpose is to help food move through our intestines, which helps us not get Diarrhea or be constipated.
Water is important since 70% of our bodies are made of water, and is found in all drinks. certain fruits also supply us with water, like strawberries and watermelons. We need it for chemical reactions in our bodies, along with making urine, which is waste and sweat, to keep our bodies cool. 

In order to keep a balanced diet, we need all of the nutrients. If we take too little, then we might contract certain diseases, or if we eat too much, then we might have too much excess fat, so that we would become obese.

Instead of using Joules for energy, we instead write the energy that food gives us with calories, so the more calories the more energy, as stated above the amount you need varies to what your doing, if your doing sports then you might need more food or energy to gain back the lost energy when doing activities, or if your growing as children need lots of energy to grow, while the elderly take less since they don't have to grow, and if your pregnant than you need to eat more since your body is forming an infant. 

Plugs and wires

One important thing about electricity is the plugs and wires, and when you need to repair them, you might notice that the different coloured wires are inside a plug.

The power that comes from the national grid is the main power supply; the current of the mains is an alternating current with around 240 volts flowing into households.
Keep in mind that the voltage may differ between which goes into our sockets in our homes.

Three wires are in a plug: the live one, the grounded or earth wire and the neutral one, all with an insulating plastic covering the copper wires.

Now, the way we differentiate the wires so that we don't shock ourselves is through the colours. brown is live, meaning all the voltage flowing through the plug is going through the brown one and has a potential difference of 230 volts. The blue one is the neutral one that will complete the circuit.
And lastly is the earth or ground wire, which is a stripped green wire that stops the plug housing from becoming live and shocking us when we grab the plug.
It does this by giving the electricity an alternative output so that the power flows out instead of into the plug housing.

The reason why the electricity from the live wire (brown) flows through the neutral wire (blue) is that they have a 0 potential difference compared to the live wire, which has, in this case, 240 volts.
Now, since humans also have 0 potential difference, we can act as a neutral wire and get shocked by electricity, too. This is why sticking forks into plug sockets even when they are "off" can still shock you, and in general, sticking things into sockets is bad.

AC & DC Current

An Alternating current which is commonly referered as AC, which is a type of current that will alternate between a positive and negitive charge, and this charge will fluctuate between voltages.
If your house is being supplied with 240 volts then the AC current will fluctuate between 240v to -240v, and it will aternate between the voltages on a set timer.

While a direct current or DC current is either a positive or negitive charge, since the positive charge is consistant, the most common use is in which makes it good for cells and batteries.

We can get graphs of the potental difference from the current is via a Oscilloscope, which measures the potental difference a current is producing by displaying it on a monitor, these monitors display the current in a wave.

How Temperature and PH levels affects the rate of reactions

Enzymes rely on temperature as the heat helps speed the reactivity, but for Enxymes to work efficiently they need to be at a stable temperature,
otherwise, if you keep increasing the heat it may break apart the bonds that hold the Enzyme together thus making the Enzyme change its active site which is where the Enzymes do their reactants if the shape change is too drastic then the Enzyme might not even help Catalyze by the Enzyme being unable to bind to the Substate.

The name of an Enzyme that has been hit with too much heat is called a Denatured Enzyme, if this does happen it is permanent and cannot be undone, Enzymes also have an optimal temperature and will work with high efficiency at a certain temperature, this is why our bodies always are 37.5 celsius.

Another deciding factor for Enzymes to be more efficient in catalysing is the PH level, which is a measurement of acidity in a substance, if the PH level is too high the rate the Enzyme can work decreases, and if the PH level too low, the Enzyme will also to be able to work at maximum efficiency. 
These changes in PH affect the Enzyme, since too low or high PH levels, change the active site of the Enzyme, sometimes it will still work but since the active site has been changed, how well the Enzyme can fit into the substrate will be worse.

Our bodies work best around 7 PH, but our stomachs work best around 2 PH since the insides of our stomachs are extremely acidic.

The National Grid

The National Grid is the network that distributes all the electricity in a city, usually the power comes from power stations, which normally produce lots of heat that then becomes thermal energy which then is turned into electricity.

The thing about power stations is that the amount of electricity they make is based on the amount of demand, the demand increases in the afternoon and evening, and since we use so much electricity in our daily lives, the power stations need to have extra capacity just in case, so often the stations run at much lower rate so that if there's a spike in electrical consumption they can output more power to satisfy the demand, which they can't do if they are running at high rates.

As we know the equation P=VT is power = voltage multiplied by time, but when high amounts of current flow through a wire, it causes the wire to heat up, this heat is then lost power, but if we need to transport this power all around the city or even the whole country this loss of power is extremely decremental.
But if we run a very low current, which is more efficient that would mean our voltage is going to be very high, meaning when we want to move the electricity around the country via the power lines and pylons we would need a way of increasing the voltage.

This is where Step-up transformers come in, they take the voltage from the power station and then turn up the voltage up to 400,000 volts then the cables transport it around the country.
Then after that, we would need a step-down transformer since 400,000 volts flowing into your house is too much if we were to pump that amount of voltage into a civilian house, firstly it would be very dangerous as if our devices or appliances they would explode having a high chance of losing lives.
In order to keep us safe from the high voltages is that we use a step-down transformer, that turns the 400,000 volts to roughly 230 volts. 

Ionic Compounds

Ionic compounds are different from ionic-bonded atoms.

As normal ionicly bonded atoms, they will lose their electrons and another element will gain them, causing the two atoms to be electrostatically attracted to each other. However, ionic compounds, have more than two atoms bonded together.

When this happens, the atoms will form in a sort of checkerboard pattern. If many atoms bond like this, the compound will be cube-shaped, which we named 'regular lattice structures." These structures will often be drawn or depicted as the cube shape. Still, with small spheres on its surfaces, another way we can depict this is we use a diagram named the "ball and stick diagram", which are similar but they instead draw or model each atom connected via a stick.

Something interesting about ionic compounds is that they have very high melting and boiling points, and they can conduct electricity, but most of the time we have to dissolve them in water or melt them down for electric conductivity, like putting salt in water to make the water more conductive, but what matters is the amount of charged particles

The boiling and melting points change depending on the strength of the bonds of atoms held together, and if the bonds in ionic compounds are very strong, more energy is required to break apart the bonds.

But if you want the ionic compound to conduct electricity, it first needs to have charged particles, if you take any solid it will be tough because all the bonds are stagnant, but if it melted or dissolved then the ions in the solid are free to move and conduct. 

In ionic compounds, one element would have to lose and one would have to gain an electron, for example, if you wish to write aa Sodium bonding with a Chlorine atom, which the Sodium has a +1 charge while the Chlorine has a -1 charge. 
So to have them bond, the Sodium would lose the electron while the Chlorine would gain one, thus, you would write this equation as NaCl+.  

But what happens if the atoms need more electrons to bond, what about Magnesium and Chloride, Magnesium needs to lose 2 electrons since it is in group 2 of the periodic table.
So the Magnesium loses 2 electrons to be a 2+ ion, then we need to balance it out, so we must take two Chlorine ions since one ion is only a -1, so if we were to write this out it would be MgCl2. 

Complex compounds like Calcium Hydroxide or Aluminium Sulfate are, more complicated as these ions aren't single elements so their atomic numbers or electron amounts are not on the table.

Instead, we will have to memorise it, for the Calcium Hydroxide is OH-, while the Aluminium Sulfate is SO42-.
Now we can look at the elements by themselves, Calcium is group 2 of the periodic table which means that Calcium or Ca has a +2 charge, while hydrogen is a -1 charge. 

Similar to the Chlorine atom, a single Hydroxide has a -1 charge, which means we need to put two of them in the CaOH- equation instead of one, the written formula for this is:
Ca(OH)2.
The reason why we put the 2 outside the brackets is because it means whatever is inside the brackets there is 2 of them. 

Now to tackle the Aluminium Sulfate, the Aluminium has a +3 charge, while the Sulfide ion has a -2 charge, this makes it a little bit more complicated because when two compounds bond they need to have the same amount of electrons.

But the problem is we can't add another electron to the Sulfate, in order for this to work we would need to first find the lowest multiple of both of the charges, which 3*2 is 6, so six is the smallest multiple we can find. 

So in order for this to work out we need 3 * 2 to get us 6, which we will take two Aluminium both of which are +3 charge, and three Sulfate ions, which means we have our 3 * 2.

So we would write this as: Al2(SO4)3. 

That's how we would write it, as we need 2 Al atoms the smaller scale 2 is there, then there is the SO4, which means the chemical writing for Sulfide, then the small 3 at the end means that there are three of the Sulfate ions. 

Other ionically bonded compounds are: NO3- for a Nitrate ion, a carbonate ion which is CO3^2-, and lastly is the Ammonium ion which is NH4+. 

Enzymes

For living organisms to survive, they need to carry out chemical reactions, which are often very slow, so to speed them up we normally apply heat to quicken the reaction.

Now, using heat has its side effects. If we use too much heat, the cells might get damaged, and it might also speed up reactions that we don't want.

In chemical and biological applications, Catalysts are substances that increase the rate that something happens and are not used up or changed,
Enzymes are biological catalysts made by living organisms. They are proteins, which are long chains of amino acids that can bend and fold, making them unique.

Enzymes work by taking a large structure, which we call a substrate, and breaking it down into smaller structures named products.
They can also do it in reverse, where they convert products into structures.

They also have a special region in them, which they can specify what they want to catalyze, and if the substrate doesn't match the catalysts, then it won't help catalyze the substrate.

There are two ways scientists thought it worked one way is the lock and key model, and then the induced fit model.
Before we figured out the induced fit model, we thought the catalyst needed to fit perfectly to the substrate being a 100% perfect match both ways, similar to what a lock and key is where the key has to be the same in order for the lock to open.

We do know now what the Enzyme will slightly reshape itself in order to help the substrate fit better, the Enzyme 'compliments' the substrate by fitting better, 

Parallel Circuits

Parallel circuits are circuits that have more than one loop, unlike series circuits, and each loop only has one component, making it more stable, meaning that if one component breaks, the whole circuit won't stop working.
We can also mix and match parallel and series circuits to add more components, an example of this is adding an on/off switch in the series circuit, which is connected to a parallel circuit.

Somthing different about parallel circuits is that since that all the compdennts get the same amout of potemntal difference, if we have a a parallel circuit with two compodents  on two loops and if the total amount of voltage going through the circuit is 4a, then either both compodents have the same amount of voltage taken (2a & 2a) each or they have an odd number like 3 & 1, if we add all of the amps in a circuit it should total to 4 reguardless. 

Eletricity likes to take the path of least-resistance, thats why electrical currents are stronger the lower the resistance the compident is, and the more compodents you add to a parallel circuit the lower the total resistsance will be,.

Ionic Bonding

As we know, atoms can bond together via ionic bonds, which happen when two atoms share the Valence electrons, which are the electrons on the outermost shell. 

Ions are created when an atom loses or gains an electron, this helps the atom to become stable, by having a full outer shell.

If we take Chlorine, which has 17 electrons in its shells and needs only one electron to form a Chlorine ion, the Chlorine atom will take that electron from another atom for example a Sodium atom or Na , which we write like this Cl+e- = Cl-.

But these don't happen by themselves, as the elections need a type of

Levels of Organization

The level of organization on the human includes: Organelles, Cells, Tissues, Organs, Organ Systems and Organisms.

Organelles are subcellular structures, things that are subcellular are Ribosomes, Mitochondria and the Nucleus.

And combined they make cells, which are all different, skin cells, blood cells, brain cells, these are specialised cells, which the scientific names of these cells are, Muscle cells, Glandular cells, and Epithelial cells. 

Next are tissues, these are groups of cells that work together to carry out functions like scar tissue, which is meant to cover up wounds to help them heal by shielding the wound from external sources, the epithelial cells combine together to make human skin along with the inside of our intestines.

The muscle tissue in our ligaments helps our body to move and flex, allowing us to grip things.

It also helps create chemicals and enzymes, like sweat, to cool our bodies and saliva, to help us digest food.

Next are our Organs. Once again, the tissues combine to make a larger structure, for example, the stomach, which breaks down food into proteins. Other things that tissues make are the lungs, teeth, bones, the digestive system and much more.

The organ's job is to 'carry out functions', which is similar to tissues, but can carry out larger processes compared to cells or tissues. These organs make systems like the Respiratory system, the Cardiovascular system, and the Reproductive system.

Then to make the whole organism, as you would need all of the organism's cells, tissues, organelles, organ systems and organs to make a functioning human body.

 

Foundation of ions.

Ions are charged particles, certain particles can form ions better than others, the reason why some elements want to become ions is because they want to have full outer shells to become stable molecules.

Elements need energy to lose or gain an Electron, so the fewer electrons an element has, the easier it is to lose them, for example, group 1 elements or the Alkali metals can lose their electrons very easily to become -2 ions.
Like group 6, which only needs to lose 2, and group 7, which only needs to gain one, groups 3-5 need to lose 3 electrons, making it harder for them.

We can depict these ions in equations, for example, an equation may look like this:
Na + e-.
This depicts a Sodium atom becoming a Sodium ion.

Cl + e- = Cl-.
This depicts a Chlorine atom becoming a Chlorine ion.

Now something to keep in mind is that when an atom is losing electrons and becoming a positive ion, then we put the electron on the right of the equation.
But if we put the electron on the left of the equation, it means the atom is combining with the electron to.

If an atom loses or gains multiple electrons, like an element like Magnesium, so we would write something like: Mg^2+ + 2e-, so this means Magnesium + 2 electrons.

Nicaragua

The country is named after the Nicaraguan tribe and Agua, which is the Spanish term for water.

Located in Central America, it is a bi-coastal nation with coasts on both the Caribbean Sea and the Pacific Ocean, located under Honduras and Costa Rica.

The border between Nicaragua and Costa Rica is just enough so that Costa Rica doesn't get access to lake Nicaragua, which is named after the countries named after, the narrowest corridor is only 2 miles wide or 3.2km, then on the border of Costa Rica they take the whole Portello lake even though it is fully enclaved in Costa Rica.

The whole country is split into 15 departments with 2 autonomous regions, their capital Managua, directly below Lake Managua or Xolotan, which is where the largest airport is, Managua's Augusto Cesar International.

Around 89% of the population lives in the south-western part of the country, the main highway, number 5, which ends in Puerto Cabezas, connecting to the Caribbean coast.

The port of Corinto, which is their largest port, often handles all the shipments. The west of the country is an uninterrupted coastline, with the east side being where all the offshore islands are.

Such as the Cayos Miskitos Biological Reserve, and the Corn Islands, strangely, the two islands beside the reserve, the Providencia and San Andes islands, belong to Colombia.

They also have territorial disputes with the USA over the island of Bajo Nuevo and the Serranilla Banks islands with Brazil.

There is also an island named Isla Calero that both Nicaragua and Costa Rica wanted to own. But then in 2016, the International Court of Justice ruled that the island belongs to Costa Rica.

Since Nicaragua doesn't have postal or street codes, they often describe where they live via landmarks and signs. And often the landmarks don't even exist anymore, so things can get confusing. They also have a unit of measurement named 'Vara', which is 84 centimetres.

They did make a rail system in 2001, but it was discontinued.

Some sites of interest include:

The National Museum, the Ruins of León Viejo, the León Cathedral, the historl city of Granada, the Masay craft market (they sell lots of hammocks), the cliff carving of El Tisey, the Revolution Museum, cigar factories, the Zapadera monoliths and petroglyphs, Apoyo lagoon, the Matagalpa chocolate factory, La Maison du Chocolat (a chocolate spa), the Casitta volcano memorial, the San Jacinto mud pools, the Cayos Miskitos stilt houses, the city of Esteli, and you can sand-board down Cerro Negro which is the youngest volcano in latin america.

They have a lot of volcanoes, as they are on the Ring of Fire, sandwiched between the North American plate and the Cocos plate, this gives Nicaragua a 'volcanic belt' which is a belt of volcanoes around the whole country, mainly dotting the south side with around 19 being active, the biggest being Sann Christobal.

Lake Managua or Xolotlan, which is the smaller one, and the largest lake, Lake Nicaragua or Cocibolca, which is the biggest lake in Nicaragua and in all of Central America.
There are many volcanoes between these lakes.

The largest two are Mototombo and Apoteque, situated near Managua, and there is Omotepe, which is an island made from the two volcanoes Maderas and Conception, situated in the middle of Lake Nicaragua.

Lake Nicaragua strangely drains to the east, flowing into the Caribbean via the San Juan river, even though the lake is roughly 10 miles from the Pacific Ocean on the west coast, while the Honduras Rio Grande De Matagalpa.

The county is divided by three regions, the Pacific lowlands which has all the volcanos and where Lake Nicaragua is, then the North Central highlands with tallest peak in the country, Mogoton, and the finally the Caribean lowlands which is near the Caribean sea and dense rainforests and near the coast is where there are swampy wetlands, and is where the most rain happens with around 635cm or 250 inces of rainfall.

Masaya volcano constantly has bubbling lava, Samoto canyon has lakes and small rivers flowing throughout the canyon, and unfortunately, Lake Managua has a pollution problem with the area around it covered in garbage.

The sad thing about Nicaragua is that it ranks as the second poorest nation in the Western hemisphere after Haiti, when you compare their nominal GDP and GDP per capita, around 40% of the population lives off a dollar a day, with 15% of their money is sent via family members that work abroad.

They are a part of the IMF, the indebted countries that help poorer countries, and they have the lowest energy generation in Central America, using oil and generators for electricity, which caused them to have an energy crisis in 2006.

But the World Energy Council has dubbed Nicaragua the world's most geothermal energy potential country, since 10% of its energy is made by volcanoes and heat.

They also have lots of animals here, including bats, jaguars, primates, along with the national bird, the Turquoise-browed Motmot.

Some food that is made and enjoyed here are: Frittinga (fried street food), Quesillo, Indio Viejo, Rondon, Chancho con yuca, Naca tamal, Vaho/Baho, Sopa mon Dongo, Pinolillo drink, Vigaron and Gallopinto.

In Central American states, they have nicknames: the Costa Ricans are Ticos, Salvadorians are Guanacos, Guatemalans are Chapin, Hondurans are Cathrachos, and Nicaraguans are Pinoleros.

They also have a saying, "Soy puro Pinolero; ¡Nicaragüense por gracia de Dios", which means "I am totally Nicaraguan Pinalero by the grace of God".

With a population of 6.824 million people, and with one out of six Nicaraguans living in either Costa Rica or the USA, the population is around 69% Mestizos, with 17% whites with Spanish heritage, with around 9% being in the black community, and the last 5% being part of the Indigenous Ameradianian groups.

Their current is the Cordoba, they use the type A American style plug outlets and they drive on the right side of the road.

They have very diverse people groups, mainly due to their colonial past, from people like Christopher Columbus to French pirates.

They have the largest population of people of African descent in Central America and most live on the Caribbean coast, most of them were brought by the British during the colonial times when the Brits colonised what was then called the Miskito coast which is named after the Miskito tribe which inhabited the area, the people living there are now named the Garifuna tribe.

Their language is English or a type of English Creole, but their National language is Spanish.

Around 20 Indigenous groups with them being the Rama, Miskito or Sumo tribes, mainly coming of Aztec or Mayan descent, also cuss and use lots of curse words, strangely enough, they have the lowest homicide/murder rate in Central America (6-7 per 100k) and are very safe to travel around.

They are Roman Catholicism at around 58%, then about 1/3 are protestant and during conflicts are disrupted the Catholic church will act as a mediator, the religion of Nicaragua is a vital part of their identity along with their traditions like the colourful clothing of the Mestizaja costumes, they are good poets which they also have lots of folklore, some nice, some creepy like the La Carretangua.

Weirdly enough a lot of the stories incorporate women, mainly ghost women like the La Ceuga, La Llorona and La Mocuana, diverting from their folklore, they also have a celebration called El Güegüense, which is on the Unesco Heritage list as an intangible heritage performed with masks and large costumes, this celebration is celebrated at the feast of Saint Sebastian.

Nicaraguans also like baseball instead of football or soccer, and their national hero, Dennis Martínez, is the first Nicaraguan who played in the MLB, with many more following suit.

The rough history is: The Native tribes in the country, Chistopher columbbus arrives and then the Spanish empire, Francisco Hernandez de Cordoba founded the first city, September 15, 1821 which is their independence from Spain, annexation from the first 1st mexican empire, then in 1823 part of the Federal Republic of Central America then 5 years later it git disbanded, then Nicaragua becomes a full country without a coloniser, then small civil wars, then Americam William Walker tries to take over the country then gets execuited via firing squad, then the Britsh relenquish the mosquito coast, then the USA occupies Nicaragua which then creates Santino's Armty which causes the Americans to leave, the Somoza Dynasty, the Sandista revolution in the 1960s-70s, they become more communist, then in 1990 they allect the first Female presedent, then the ecomony starts to recover, then Sandista party returns thing become slighty heated due to theor past then after awhile the economy starts growing more, then protests agebst the government.

Some people of Nicaraguan descent or with Nicaraguan heritage are: Augusto Cesar Sandino, Arlen Sui, Violeta Chamorro, Ruben Dario, Daisy Zamora, Eddy Kühl Aráuz, Luiz Enrique Hernaldo Zuñiga, Tony Meléndez, Salvador and Katia Cardenal, Bianca Jagger (Mick Jagger's first wife), Michelle Richerson, Alexis Arguello, Michelle Richerson, Alexis Arguello, Román Chocolatito González and Claudia Poll.

Some countries that have close ties with Taiwan, South Ossetia, and Kasnia, Taiwan helped them by giving them a 100 million dollar loan during the protests, which the President Ortega accepted. 

Although the USA has some rough patches with Nicaragua, they are still the largest import and export partner, and the US has the largest community of Nicaraguans in Miami.

Cuba, Venezuela and Bolivia have an alliance with Nicaragua named the "Alianza Bolivariana Para Los Pueblos De Nuestra America" or the Bolivarian Alliance for the People of our America; they all support the ideas of Simón Bolívar and socialist based governments. Cuba provided grants and development funds during the 70s and 80s, Venezuela provided Nicaragua with Oil.

Other Central American countries share an Independence Day on September 15. In 2006, they signed the CA-4, the Central America 4 Free agreement, which allows free movement between Honduras, Guatemala, and El Salvador.

Specialised Exchange Surfaces

These types of exchange surfaces are parts of an organism that exchange substances with the exterior envorment. 

Our exchange cells in our bodies are the Villi, and the Alveoli.
Its job is to exchange Oxygen and Carbon dioxide in our blood, but the Villi, which are our intestines, help with absorbing glucose and amino acids.

The roots in the bottom of the plant have their root hair cells, which help absorb the water in the surrounding soil, along with the leaves, to help them absorb CO2  in the air.

Something to help with these exchange surfaces is a large surface area, so by having hundreds of millions of Alveoli in our lungs, it makes it a larger surface area, having a large surface area increases the amount of diffusion and can also help with the diffusion rates. 

Another thing about diffusion surfaces is that they are often very thin because it makes the substances diffuse over a short distance, for root hair cells, the water only has to diffuse through a thin cell wall and membrane,
this is known as a 'short diffusion distance', which increased the speed with which the plant can absorb. 

Other types of diffusion surfaces are blood, as the blood has to flow and diffuse throughout the body, so having glucose dissolve into the blood that gets taken away to the intestines to then be replaced by more blood.

Another good thing to keep in mind is a 'good supply of external mediums', a good example of this is keeping a good supply of Oxygen for your lungs, when you breathe the Oxygen mixed with the Alveoli, which helps keep a steady concentration gradient for your bloodstream.

Series Circuits

Learning the difference between Series and Parallel circuits is important. 

In series circuits, the components are added in 'series' or in one line, as if they were all on one wire. The thing about this type of circuit is that if the wires break, the whole circuit stops working.
This also means that the potential difference is shared throughout the circuit.

You might get an equation like this :
Vtotal = V1 + V2 + V3.

If we were to put a 12-volt cell or battery, and have two filament lamps on the circuit, both lamps have to add up to 12 volts

On the other hand, current is the same everywhere in the circuit. To measure it, we use ammeters, which are placed in series, and since they measure current, we can place them anywhere in the circuit.

Resistance is how much the component resists electricity, and the total resistance is a sum of how much all components resist, so to calculate the resistance in ohms, we need to know how much power our components resist. 

So, let's take a circuit and connect two filament lamps, one lamp requires 4 ohms, and the other requires 2 ohms.
The total amount of ohms is about 6 ohms, since it is 2 + 4.

Let's use the same 6 ohm circuit above and calculate the resistance of a single component.
We can use the equation "V=IR", which is named Ohm's law, the 'V' in the equation means voltage.
So, first we find the battery, which is 12v or 12 volts. 
We then divide the 12 volts by 6 because that's how many ohms are flowing into the circuit, to get 2A or two Ammeters, then which then means that the component had 2A of resistance, then we multiply the 2A by 2 ohms or 2*2 to get 4 volts. 

Something to keep in mind is that Ammeters do have resistances, it is such tiny resistances that we can practically ignore them, now if we want to get the voltage of the second component, we would need to do the equation again, or we could just do 12-4 to get us 8.

Because we know how many volts are flowing through the circuit, which is 12, we can just skip doing the math, so doing 12-4 gives us 8, so that means that the second component needs 8 volts.

There is another way to find out how much voltage each component uses in the circuit by using a Voltmeter, which is connected in parallel to the component which we want to check, so if we connect it to the 8 volt component, it would display 8v.

Keep in mind that even though the voltmeter is connected in parallel,
we still consider the circuit to be in series, also the components that have a higher resistance will require more voltage, than components that resist less.