Answer: D. Enzymes can denature (lose their shape) and stop working if temperature or pH is out of their healthy range.
Step-by-step explanation:
Enzymes are highly specific and selective of their environment and substrate. There are temperatures and pH range in which they are highly effective and best operate in. Those temperatures and pH are called their optimal range. Should those environmental conditions change (pH of ocean water) they will easily lose shape, a process called denaturing.
When they denature, their substrate cannot recognize them and are left unable to bind to enzyme's active site, thus cannot form an enzyme-substrate complex to proceed with catalyzing the reaction.