Which of the following best explains how human activities can directly contribute to landslides?
a.
removing plants from hillsides eliminates the root structures that anchor soil.
b.
clearing trees from hills increases the frequency of rainstorms.
c.
human activities tend to reduce the risk of fires.
d.
landslides are not impacted by human activities.

The answer is A.

Explanation:

Many natural incidents and human activities effect landslides. But since the recent past, human activities have been the major contributor towards the increasing landslide incidents.

Deforestation and the removal of plants and trees from hillsides may be the most contributory fact to the landslides. The roots of these plants and trees act as a strengthening force that holds the soil during wet seasons where the water level in soil increases significantly.

Just as the answer say, when the trees are removed, this "anchor" is also removed and since their is no force to keep the wet soil together, the landslides occur.

Other options in this question are either incorrect or not related.

A

Explanation: I got it right in the exam

.) the observation by semmelweis that more mothers died of childbed fever when their doctors also worked in the morgue

see earlier