Which endocrine gland releases hormones that regulate the rest of the endocrine system?
a. pituitary gland
b. pancreas
c. adrenal gland
d. thyroid

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.

Which line in the graph above best illustrates an effect of the carbon dioxide level in the blood on breathing rate before, during and after a period of exercise? 1.b,2.c,3.a,4.d

What do genes contain the code for?