Which of the following was an early realization that gave rise to darwin's theory of natural selection? a. most organisms share the same habitat. b. the earth is younger than previously thought. c. organisms do not appear to be closely related. d. the earth and its organisms have changed through time.

What is a difference between systemic and pulmonary circulation? a. systemic circulation carries oxygenated blood to the lungs and pulmonary circulation carries deoxygenated blood to the body. b. systemic circulation carries deoxygenated blood to the lungs and pulmonary circulation carries oxygenated blood to the body. c. systemic circulation carries deoxygenated blood to the body and pulmonary circulation carries oxygenated blood to the lungs. d. systemic circulation carries oxygenated blood to the body and pulmonary circulation carries deoxygenated blood to the lungs.