B
If deep-sea divers ascend too rapidly from ocean depths, the decreasing pressure causes nitrogen to be released as gas bubbles in the blood. This condition is known as "the bends. " Sea snakes, who, like humans, breathe air that contributes nitrogen to the blood, are nevertheless able to make extremely rapid ascents and descents in ocean waters without suffering from the bends. Which one of the following, if true, contributes most to an explanation of the difference described between humans and sea snakes?
A: Human deep-sea divers are trained to make several stops on ascending from deep water in order to adjust to decreasing pressure gradually, whereas sea snakes ascend from ocean depths without stopping.
B: Sea snakes, unlike humans, can excrete nitrogen from their blood into the sea by means of extremely small blood vessels beneath their skin.
C: A rapid release of bubbles of nitrogen gas into the blood inhibits circulation and can deprive organs of the blood they need to function.
D: The rapidity with which sea snakes are able to descend or ascend in ocean water is partially determined by the degree of buoyancy permitted by the inflation of the sea snake's lung.