Which of the following is an example of an external force that affects the Earth's surface?

The correct answer highlights how external forces, such as pollution and severe weather, can significantly affect the Earth's surface. Pollution can lead to soil degradation, contamination of water sources, and can alter the ecosystem, causing long-term changes to the landscape. Severe weather, including hurricanes, floods, and erosion from heavy rainfall, can physically reshape the Earth's surface through processes such as erosion, sediment deposition, and destruction of habitats.

Movement of tectonic plates is considered an internal force. This process occurs beneath the Earth's crust and is responsible for geological phenomena such as earthquakes and mountain formation, but it does not qualify as an external force impacting the surface directly in the context of this question.

Geological formations relate to the Earth's intrinsic characteristics and are the result of internal processes over geological time. While they influence surface conditions, they are not classified as external forces.

Soil fertility pertains to the capability of soil to sustain plant growth, which is influenced by both internal soil properties and external factors such as climate and weather conditions, but it does not directly classify as an external force acting on the Earth's surface.