Final answer:
A theory is a broad idea that can be used to make predictions about future observations and is supported by many experiments. It differs from a hypothesis, which is a testable prediction, and a conclusion, which is the end result of an experiment.
Step-by-step explanation:
Theory is a broad idea that can be used to make predictions about future observations. Unlike a hypothesis, which is a tentative explanation that can be tested, a theory is a well-substantiated explanation of an aspect of the natural world that has been repeatedly tested and supported by many experiments. A fact is something that has been confirmed to such a degree that it would be reasonable to offer provisional agreement, but it is not as broad as a theory which can help explain facts.
An experiment is a procedure carried out to test a hypothesis, not a broad idea itself. A conclusion is the end result of an experiment that determines whether the hypothesis was supported or not. Therefore, when discussing something that can make predictions about future observations in science, the correct answer is 'theory.'