Answer:
theory
Explanation:
A scientist can contribute to the formation of a theory in a particular subject by conducting research along the line of that subject.
Conducting research requires the formation of a hypothesis and testing the hypothesis by conducting a relevant experiment during which data are gathered, analyzed, and interpreted in order to falsify or accept the hypothesis.
A good experiment must be replicate-able. When the same experiment is repeated by different independent researchers and the same conclusion is arrived at, this could potentially lead to the formation of a theory.
Hence, a scientist can contribute to the formation of a theory by conducting an experiment with replicability in order to test a hypothesis.
