What does “residence time” mean in the global water cycle?

Correct answer: The average time a water molecule spends in a particular reservoir, such as the atmosphere or ocean

Direct answer: B. A reservoir is a place where water is stored, such as the atmosphere, an ocean, a glacier, a lake, or groundwater. Residence time is the average length of time water remains in one such reservoir before moving to another through evaporation, precipitation, runoff, infiltration, melting, or other processes. It is not the exact time for every individual molecule; it is a useful average for understanding turnover. A concerns boiling and is unrelated to storage. C gives the length of one rainfall event, not the average storage period. D describes a possible drying interval and is not the general definition. Residence times differ greatly among reservoirs: atmospheric water is generally short-lived, while deep groundwater, ice, and some ocean water may remain much longer. Memory cue: residence time means “how long water stays before changing residence.”