The protein that helps make vertebrate skin tougher and more waterproof is:
a. collagen
b. elastin
c. hemoglobin
d. keratin
e. melanin
d
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Reinforcement is most likely to occur when _____
A) the environment is changing B) hybrids have lower fitness than either parent population C) prezygotic isolating mechanisms are in place D) gene flow is low
A population of lizards lives in a rocky area next to a desert. Some lizards are light colored and blend into the sand. Others are dark and blend into the rocks. What may happen to this population of lizards over time?
A. They may evolve into two separate species as a result of directional selection. B. They may remain one species as a result of stabilizing selection. C. They may remain one species as a result of disruptive selection. D. They may evolve into two separate species as a result of disruptive selection. E. They may remain one species as a result of directional selection.
Solution A has a pH of 6 and solution B has a pH of 8. Therefore, ____
a. A has 10 times greater H+ concentration than B. b. B has 10 times greater H+ concentration than A. c. A has 100 times greater H+ concentration than B. d. B has 100 times greater H+ concentration than A. e. A has 1,000 times greater H+ concentration than B.
Oxygen moves from alveoli to the bloodstream
a. because the concentration of oxygen is greater in alveoli than in the blood. b. mainly due to the activity of carbonic anhydrase in the red blood cells. c. because of its attraction to hemoglobin. d. to counter the high concentration of CO2 in the blood. e. because of all of these