Water vapor evaporated from the ocean contains a greater proportion of oxygen-16 and a smaller proportion of the heavier oxygen-18 than does seawater. Normally, this phenomenon has no effect on the overall composition of the ocean, because evaporated seawater returns to the ocean through precipitation. During an ice age, however, a large amount of precipitation falls on ice caps, where it is trapped as ice.
Which one of the following conclusions about a typical ice age is most strongly supported by the statements above?OPTIONS
[A]. The proportions of oxygen-16 and oxygen-18 are the same in vapor from seawater as in the seawater itself.
[B]. The concentration of oxygen-18 in seawater is increased.
[C]. Rain and snow contain relatively more oxygen-16 than they do in interglacial periods.
[D]. During the ice age, more of the Earth’s precipitation falls over land than falls over the ocean.
[E]. The composition of seawater changes more slowly than it does in interglacial periods.
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