How can a simulation help you investigate the effects of resource availability on populations?

Apart of an ecosystem that can restrict the growth of a population is referred to as

The vaccine in a flu shot contains weakened flu viruses. how does a flu shot work with the immune system? a. it destroys lymphocytes. b. it destroys macrophages. c. it activates macrophages. d. it activates lymphocytes.

Body temperature is tightly regulated in mammals for example when external temperatures drop too much the body of a mammal responds by in order to its core temperature?