Explanation:
A model is used to help scientists visualise things that they cannot actually see. It can be thought of as a thinking tool, to help form explanations. Models are useful simplifications to aid understanding. ... It can then be used to explain further phenomena and to make predictions of future behaviour.
I think the hormone would be testosterone, it would be subjectively deemed useless in times other than procreation. I would suggest that the important hormone is the growth hormone Thank you for your question.
Answer:
cellular respiration because glucose is metabolized with oxygen to form carbon dioxide energy and water
