Answer:
A scientist examined a population of Schinus terebinthifolius (Brazilian pepper trees) after a hurricane to measure the effects of the storm. No alteration of variables occurred before or after the event. This is an example of a NATURAL experiment.
Explanation:
A natural experiment corresponds to a different investigation strategy. This design or methodologic model characterizes because the researcher does not intervene in the creation of treatment and control groups. There is an exogenous agent, such as a natural phenomenon, that influences the study groups. The researcher takes advantage of these events to use these random groups to compare them in the study. The researcher chooses exposed groups that might have been affected by the natural event and other groups that have not been affected.
In the exposed example, the natural disaster is the hurricane, which is the exogenous agent. The study objective was to measure the effects of the storm on the Brazilian pepper trees population. And the exposed group is the population of Schinus terebinthifolius examined.
