Question

what is a cause of mechanical weathering?

rainwater

sunlight

natural acids

physical forces

Explanation:

Mechanical weathering is the physical breakdown of rocks without changing their chemical composition. Rainwater can contribute to chemical weathering (e.g., dissolution) or mechanical (like freeze - thaw, but the option "rainwater" is not the best general cause). Sunlight mainly causes thermal expansion/contraction which is a physical force - related process, but "sunlight" is not the direct cause term. Natural acids cause chemical weathering (chemical reactions). Physical forces (like pressure changes, freeze - thaw, plant roots, etc.) directly cause the physical breakdown of rocks, which is mechanical weathering.

Answer:

D. physical forces