Question

As a cloud drifts northward from the equator, steadily losing moisture through precipitation on its journey, the 18O/16O ratio of the precipitation from the cloud would most likely:

a) Decrease
b) Increase
c) Remain constant
d) Fluctuate randomly

Answer 1

The 18O/16O ratio of precipitation from a cloud moving northward from the equator would increase because molecules with 16O precipitate out first, enriching the remaining moisture in 18O.

Step-by-step explanation:

As a cloud drifts northward from the equator and steadily loses moisture through precipitation, the 18O/16O ratio of the precipitation from the cloud would most likely increase. This is because oxygen-18 (18O) is heavier than oxygen-16 (16O), and when water vapor condenses into precipitation, molecules containing 16O are more likely to be removed by precipitation first. Since the lighter isotopes precipitate out more readily, the remaining water vapor, and subsequently the later precipitation, becomes enriched with 18O, resulting in an increased 18O/16O ratio as the cloud moves away from the equator and loses moisture.