What type of water movement occurs in soil as water moves downward?

The correct choice identifies gravity as the primary force that drives the downward movement of water in soil. When water infiltrates the soil surface, gravity pulls it down through the soil profile, allowing it to percolate deeper into the ground. This process is essential for replenishing aquifers and providing moisture to plant roots.

While capillary action involves water moving upward or laterally against gravity due to adhesion to soil particles, it does not primarily facilitate downward movement. Permeation refers to the movement of water through soil or porous materials but does not specifically describe the force driving the downward movement. Evapotranspiration encompasses the processes of evaporation and plant transpiration, which lead to water loss from the soil but do not directly relate to the downward movement of water within the soil.