Species change over time. -The mechanism that produces the change is natural selection: the differential survival and reproduction of individuals based on variation in their traits. Natural selection acts on individuals but individuals do not evolve; their descendants do.
Answer:
For regulating activities of cell.
Explanation:
Ad nucleus consists of genetic materials like DNA,RNA which is responsible for controlling and directing all the activities of cell.
The capability of both leptin and cholecystokinin in which they
have a similarity when a person has decreased its food intake. A leptin is a
way of helping an individual to regulate energy in means of having to inhibit
its hunger while the cholecystokinin is responsible for having to stimulate
digestions.
