Answer:
4) theory
Step-by-step explanation:
Science is a branch of study that deals with answering questions and solving problems. However, there are different scientific principles used to tackle the problems in science. One of them is a THEORY, which is a detailed and well explained fact about a natural phenomena. A theory is said to be an hypothesis that has been subjected to series of experimental testing and found to be accurate or consistent.
In this question, a series of experiments was designed and conducted by several science teachers around the world. The results were found to be consistent that students who stayed up all night playing before their finals did -40% worse than students who didn't. This comprehensive and well explained observation using repeated experiments depicts a THEORY.