The human body is made of a group of systems that function together. therefore, communication between these systems is crucial. describe two ways communication occurs within the human body. for each example, brainstorm how the body would be affected if this type of communication could not occur.

Which conditions are necessary for natural selection to occur? select all of the answers that apply. a. inheritable adaptations vary among individuals. b. the population size is increasing. c. more individuals are born than can survive. d. fitness varies among individuals. e. the environment changes suddenly and drastically.

The chemical form of energy that is useable by the cell to do work

Why do we perceive objects as retaining their brightness under different lighting levels?