How should the experimenter control the light exposure for frogs in a study on its effects?

In a study examining the effects of light exposure on frogs, controlling the light conditions is crucial to ensure that the results are reliable and interpretable. The choice of exposing other frogs to day and night conditions allows the experimenter to create a controlled environment that mimics natural light cycles. This is essential because many biological processes, such as hormone production, behavior, and physiological responses, are influenced by the natural light-dark cycle.

By selecting this option, the experimenter is able to provide a variable that can be measured and compared against the frogs exposed to different light conditions. This can help to determine how varying levels of light—such as exposure during the day and protection from light at night—affect the frogs in terms of their health, behaviors, and other pertinent metrics.

In contrast, keeping the frogs in total darkness would not provide any light exposure to measure its effects, chronic exposure to fluorescent light might not adequately replicate natural conditions, and perpetual daylight conditions could cause stress or skew the results in ways that are unrelated to the desired effects of light exposure. Therefore, the most scientifically sound approach is to utilize a day-night cycle as a control for comparing effects across different light exposure scenarios.