Rainfall patterns depend on (d) the prevailing season in an area.
Explanation: The prevailing season dictates the overall climate conditions in a region, including temperature and humidity, which significantly influence the amount and frequency of rainfall. Different seasons bring different weather patterns, with some promoting more rain than others. For example, monsoon seasons are characterized by heavy rainfall, while dry seasons typically have little to no precipitation.
Why other options are incorrect:
(a) the underground water table:
While the underground water table can affect local water availability, its direct impact on rainfall patterns is minimal. The amount of rain primarily depends on atmospheric conditions, not the subsurface water storage.
(b) the number of water bodies in an area:
While more water bodies can contribute to increased evaporation, this is only one factor in the complex process of rainfall formation. Factors like atmospheric circulation and prevailing weather patterns play a more crucial role.
(c) the density pattern of human population:
Human population density does not directly influence rainfall patterns. Rainfall is a natural phenomenon primarily driven by climatic conditions, and human activity has a limited impact on it, although certain practices like deforestation can indirectly affect local climate patterns over time.