Calculate the difference in blood pressure between the feet and top of the head.

this is an incomplete question but pressure is said to decrease with height and increase with depth.

This means pressure at the top of the head is lower than pressure at the feet.

It is taken that blood pressure at the arms is roughly 10% lower than blood pressure at the legs.

Explanation:

the answer is yes, they are born/created, then they grow to their limit then produce offspring, then die.

i believe it is "they are not used up by reactions" as the answer to your question, text me back if this is correct because i just learned this.