If the soil of a region becomes completely water-saturated, what will happen during subsequent rainfall?

Correct answer: Surface runoff will increase greatly and may cause flooding

Correct answer: B. Infiltration is the entry of water into soil. At first, unsaturated soil can accept rainfall because its pore spaces contain air and available storage remains. Once the soil becomes saturated, most relevant pore spaces are already filled with water, so the soil cannot accept additional rainfall at the same rate. Rain falling faster than the remaining infiltration capacity therefore accumulates and moves across the land as surface runoff. If rainfall is intense or the land is low-lying, this runoff can produce waterlogging or flooding. A is wrong because saturation generally limits, rather than increases, infiltration capacity. C is wrong because soil saturation does not automatically stop all plant transpiration. D is wrong because additional infiltration is limited and groundwater need not fall; the immediate result is greater runoff. Memory cue: full soil pores leave rainfall with nowhere to go but over the surface.