Facilitated diffusion
i also included a photo of the explanation of facilitated diffusion. i hope this is helpful
At the beginning of the follicular phase, the lining of the uterus (endometrium) is thick with fluids and nutrients designed to nourish an embryo. If no egg has been fertilized, estrogen and progesterone levels are low. As a result, the top layers of the endometrium are shed, and menstrual bleeding occurs.
Answer:
A population changes in response to a change in the environment.
Explanation:
The changes in a population( variations) are due to changes in the environment. These variations confers an advantage to those individual possessing them. This enables such individuals to stand a better chance to survive in the struggle for existence. The better adapted individuals are able to survive and reach the reproductive age and pass over their favourable traits to their offspring.