People contribute to changes in the Earth's physical condition.Through
Soil erosion and other degradation of grazing land,often at the hands of
People,an estimated __________ tons of topsoil is lost annually.

Question

Quizplus · Accepted Answer

According to the given information in the question, an estimated amount of topsoil lost annually is in billions, so the only option that provides a possible answer in billions is D, which states "25 billion." Therefore, D is the best choice.

People Contribute to Changes in the Earth's Physical Condition