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Alveoli are small sacs at the end of the terminal branches of the lung (the brochioles). It is at the alveoli where gas exchange takes place - oxygen moves into the blood and carbon dioxide is removed. Th...

Homeostasis is defined as the maintenance of a constant internal environment in the body. 

An example of this would be the blood glucose level:

After a meal, a person's bloo...

Spread of mutations via vertical and horizontal transmission

Once a bacterium has a mutation that provides resistance to an antibiotic, it can spread through replication or through...

Photosynthesis requires optimal temperatures, high levels of light, and carbon dioxide.

The limiting factor of photosynthesis is the fac...

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Within all populations, there is variation.

This is due to di...