An is when you gather facts through observation, questioning, or studying.
What would be in the blank? Will mark Brainliest for best answer.

An Experiment

Explanation:

To understand and explain the natural events, the scientific method is followed which refers to the systematic approach to understand the work. A scientific experiment is one of the step of the scientific method which is used to test the predicted statement which could explain the event.

The experiment includes the observations related to the predicted hypothesis and to answer the scientific question. The observation can produce facts which could prove or disprove the hypothesis.

Thus, an experiment is the correct answer.

Observational study

Explanation:

An observational study can be defined as the study which involves the observation of the object or subject under study, developing question which is to be answered scientifically using proper methodology to obtain data and analyze it to derive a conclusion. The observational studies does not involve the self-manipulation or treatment on the subject. The case control studies and cohort studies are the examples of observational study.