Answer:
D. Feel-good/pleasure
I hope I helped!
Function of an enzyme is to lower reaction's activation energy and to increase speed of a reaction, but to make it happen, enzyme and substrate must fit spatially. The shape of an enzyme is essential to make enzyme-substrate complex - if active site of an enzyme doesn't fit to substrate, there won't be a enzyme-catalised reaction.
Answer:
inflates itself when scared
Explanation:
Homeostasis is the process by which organisms undergo to maintain a constant internal environment for internal processes to occur. Hence, the answer would be that which acts to counter any external stimuli which causes change in the body's environment, not simply factors involved in the survival of the species such as feeding and camouflaging.