Populations at genetic equilibrium occur in nature.
1 often
2 occasionally
3 always
4 never

humans are now responsible for causing changes in the environment that hurt animals and plant species. we take up more space on earth for our homes and cities. we pollute habitats. human activity often changes or destroys the habitats that plants and animals need to survive.

stimulus is a change in the environment that causes an organism to react. the response is the reaction to the stimulus. some examples of stimuli for zebras are drought, to many predators, and bad feeding grounds such as dead grass or plants. zebras respond to stimuli just like all other living organisms

a plastic spoon that has a temperature of 78° f is placed into a bowl of soup that has a temperature of 84° f. which of these correctly describes what will happen?

energy as heat moves from the soup to the spoon.