Question

what is the biggest agent of erosion?
human activity
water
gravity
wind

Explanation:

Water is a major agent of erosion. It can erode through processes like runoff, rivers flowing, and ocean waves. Human activity can cause erosion but is not the biggest natural agent. Gravity causes mass - wasting which is a form of erosion but water has a more widespread and significant impact. Wind erosion is important in arid regions but overall water is more dominant.

Answer:

water