Which of the following is most likely to move through the cell membrane by facilitated diffusion?

a. small lipids b. na+
c. co2 d. o2

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 of the following is a period in the paleozoic era? devonian cambrian permian all of the above

What term describes a doctor who becomes a specialist by meeting standards beyond those of getting a license and passing a test in the specialty area?