Linked from
The 9 pages that link to Entrainment, each with the reason it gives.
NocturnalityRelated: Light and other cues can set the phase of nocturnal activity.
Cumulus cloudRelated: Dry air entrained into a cloud can evaporate droplets and weaken its updraft.
Diurnal animalRelated: Light-dark cycles can reset an animal’s daily clock.
Cumulus mediocrisRelated: Dry environmental air can weaken the updraft and restrain further growth.