13. Exponential, limiting
14. Keystone
15. Population (not completely sure on this one, may be something like biodiversity)
They are all part of the digestive system, they all break down food, they all have enzymes
It is chemical because of the heat and gas which causes air bubbles
Answer: Structure refers to how the body is put together-bones, muscles, tendons, and ligaments. Then onto the organ structure, down to the cellular level. Function refers to body work.
Explanation: I know this is right cause I had a test on this question before.
