Question

Fill in the blank with the most suitable option:
It can be inferred from the passage that precipitation formed from evaporated ocean water has ______________.

• A. The same isotopic ratio as ocean water
• B. Less oxygen 18 than does ocean water
• C. Less oxygen 18 than has the ice contained in continental ice sheets
• D. A different isotopic composition than has precipitation formed from water on land
• E. More oxygen 16 than has precipitation formed from fresh water

Answer 1

Answer: (B)

Less oxygen 18 than does ocean water

The third sentence from the third paragraph explains how heavier isotopes, which are oxygen 18, are left behind when water evaporates from the ocean. This proves that precipitation forming from ocean water has less oxygen 18 because it's left behind. Thus, B is correct.

We need not consider the other options.