Which rhythm is influenced directly by external cues such as sunlight?

The rhythm that is influenced directly by external cues such as sunlight is best described as an exogenous rhythm. Exogenous rhythms are those that are directly affected by environmental factors, including light and temperature, which serve as cues that help organisms synchronize their biological processes with the external environment.

In the case of sunlight, the daily cycle of light and dark acts as a powerful signal that influences various physiological activities. For example, many plants and animals display behaviors such as flowering, feeding, and mating that are timed according to the presence or absence of light, aligning their internal biological clocks with day-night cycles.

Circadian rhythms, while also related to light, refer specifically to biological processes that follow a roughly 24-hour cycle influenced by external cues. Endogenous rhythms describe internal biological clocks that run independently of external cues, such as those that might continue to operate even in constant conditions. Home range is not a rhythm but rather refers to the area occupied by an animal during its normal activities.

Thus, exogenous rhythms are directly tied to environmental signals, making this the appropriate answer to the question of which rhythm is influenced by external cues such as sunlight.