Which of the following terms best describes a controlled experiment involving population dynamics?

A controlled experiment involving population dynamics is best described as an ex situ experiment. Ex situ experiments are conducted outside of the natural environment where the population usually exists. This allows researchers to manipulate various environmental factors, monitor specific population changes, and gain insights into population dynamics under controlled conditions. Such experiments can provide clear cause-and-effect relationships, which may be more difficult to discern in a natural setting where numerous variables are at play.

In contrast, field studies typically take place in the natural habitat, which can introduce uncontrolled variables affecting population dynamics. Longitudinal studies involve repeated observations of the same variables over long periods, focusing on changes over time rather than controlled experimental conditions. In situ experiments are conducted in the natural environment, offering realism but lacking the control necessary for dissecting specific population interactions. Thus, ex situ experiments provide the necessary control to study population dynamics effectively.