Answer:
They are a main source of energy
Explanation:
they give us energy, they help our brain, kidneys nervous system and heart muscles
I think its c.
but i dont know for sure.
Answer:
the main site of gas exchange is in the lungs between the alveoli and a family of really small blood vessels called capillaries. Which are placed in the walls of the alveoli.
Explanation:
Stress is "your body´s way of responding to any kind of demand". It might be cause by good or bad experiences. it might be caused for many reasons: physical reason such as fear, or emotional like family or job. So it could be said that a person height might not influence stress because it has to do with something biological, a human conditions and not an external factor. <span />