Earth Science and Geology Practice Exam 2026 - Free Practice Questions and Study Guide

The main idea is that human actions remove protection for soil and disrupt its structure, causing erosion to happen more quickly and soils to deteriorate. Deforestation takes away trees and their roots that hold soil in place and the canopy that shields soil from impact of heavy rain, so rain can detach and wash away more soil. Overgrazing reduces ground cover and often compacts the soil, which lowers infiltration and increases surface runoff that carries soil particles away. Urban development replaces natural land with roads and buildings, creating impervious surfaces that funnel rain into fast runoff and transport sediment into streams. Poor agricultural practices—like deep, frequent tillage, leaving soil bare for long periods, and not maintaining soil organic matter—break down soil structure, reduce aggregation and porosity, hasten nutrient loss, and make soil more susceptible to both wind and water erosion.

Natural climate cycles can influence erosion, but they don’t describe the direct impact of human actions; selective planting of cover crops would actually help prevent erosion rather than accelerate it; and volcanic activity isn’t a typical human-driven factor and wouldn’t be described as increasing rainfall intensity in a way that broadly accelerates erosion.