An impulse that travels inward from a sensory receptor to the spinal cord, then outward to a muscle is called a(n)

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.

Why do carbohydrate molecules function so well as fuel for the body?

Which image shows labeled organelles that are present only in plant cells?