Groundwater that flows through different pores at different rates and flow paths that vary in length is caused by what process?

The correct answer is dispersion. This process describes how groundwater moves through a porous medium, such as soil or rock, where variations in pore size, connectivity, and structure lead to differences in flow rates and paths. Dispersion refers to the spreading of a fluid, in this case, groundwater, due to these variations, resulting in some water flowing more quickly through larger pores while other water flows more slowly through smaller pores or convoluted pathways.

Dispersion is crucial in understanding groundwater quality and transport of contaminants, as it helps explain why certain solutes might travel at different speeds and distances in an aquifer. By recognizing the impact of pore variability on groundwater movement, we can better predict the behavior of water in subsurface environments.

Other processes such as absorption, filtration, and permeation do not accurately capture the concept of variable flow rates through different pores, as they focus on different aspects of water interactions with materials rather than the variability of movement throughout a porous medium.