The answer is a carrying capacity.
The carrying capacity is the maximum size of some population, for example, wolves population, that can survive in the given environment, in this case, the forest. It represents the number of animals that can live, reproduce, survive in the given area regarding the indefinite sustainability of this area in terms of resources (food, water, habitat, etc.)
I think the first one is right !.... but the for the other one it's B .
The evolution of sexual reproduction is a great puzzle in modern evolutionary biology. Many groups of eukaryotic organisms, especially most animals and plants, reproduce sexually. The evolution of sex between two organisms of the same species contains two related but different themes: its origin and its maintenance. However, since hypotheses for the origin of sex are difficult to test experimentally, most of the current work has focused on the maintenance of sexual reproduction. Biologists, including W. D. Hamilton, Alexei Kondrashov, and George C. Williams, have proposed various explanations for how sexual reproduction is maintained in a large set of different living things.
C) it regulates what goes in and out of the cell
Usually the membrane is the organelles that acts like a door. They decide what type of nutrients and molecules go into the cell.
