The direction of movement of capillary water in soil is primarily determined by what?

Correct answer: The soil-water-potential gradient

Direct answer: B, the soil-water-potential gradient. Capillary water is held in small spaces between soil particles and can move through those spaces. Water moves spontaneously from a region of relatively higher water potential to a region of lower water potential. A dry region usually has a more negative matric or water potential than a wet region, so capillary water is drawn toward the drier region. Gravity can influence movement, especially in larger pores and during downward drainage, but it is not the primary explanation for capillary movement in this question. C is wrong because wind acts on exposed air, not as the main force inside soil pores. D is not a scientific rule: colour does not determine direction, and density alone is insufficient. Memory cue: “water follows the potential gradient,” not simply the compass direction or wind.