How does adding regulatory molecules affect the enzyme activity?

Sea stars, sea urchins, sand dollars, and brittle stars are all memeber of a group, what is the common name of the group they are all in

Which of these would most likely be a stimulus that would cause the body to initiate feedback mechanisms a.) normal body temperature in an arctic environment b.) normal boy temperature in a tropical environment c.)light physical activity d.)low blood sugar

What happens when a population reaches its carrying capacity