Question

suppose the researchers locate a colony of coral established in a natural setting, and begin collecting data on the percentage bleaching in the colony at regular time intervals. they observe that the percentage bleaching increases just after the water temperatures are observed to rise dramatically. how would this investigation be classified?
controlled experiment
variable experiment
comparative experiment
predictive experiment

Explanation:

In a controlled experiment, conditions are deliberately manipulated. Here, researchers are just observing the natural - occurring relationship between water temperature rise and coral bleaching without controlling any variables. A variable experiment is not a standard scientific experiment type. A comparative experiment involves comparing different groups or conditions. A predictive experiment aims to predict future events based on current data. Since the researchers are simply observing the relationship between two naturally - occurring phenomena (water temperature and coral bleaching) without manipulation, this is not a controlled experiment. It is more of an observational study, but among the given options, it doesn't fit any perfectly. However, if we consider that they are observing the relationship between variables (water temperature and coral bleaching), it is closest to a comparative experiment as they are looking at how one variable (water temperature) affects another (coral bleaching).

Answer:

Comparative experiment