Which of the following is NOT one of the elements of the hydrological cycle?

The hydrological cycle, also known as the water cycle, consists of several key processes through which water is circulated throughout the Earth and its atmosphere. These processes include evaporation, where water is converted from liquid to vapor; transpiration, which is the release of water vapor from plants into the atmosphere; and runoff, referring to the movement of water, usually from precipitation, across the ground and into bodies of water.

Filtration, on the other hand, is not a process that is typically classified as part of the hydrological cycle. While filtration can occur as water moves through soil and other media, effectively cleaning and purifying it, it is more related to water treatment processes rather than a primary element that describes the movement and phases of water in the natural cycle. This distinction is important, as the elements of the hydrological cycle focus specifically on how water moves in its various states rather than how it may be treated or filtered.