Question

what is chemistry the study of?
the study of living organisms
the study of historical events
the study of what matter is made of, how its structured, and how it changes or reacts with other substances
the study of rocks and other geologic features

Explanation:

Chemistry focuses on matter - its composition, structure, and chemical reactions. The study of living organisms is biology, historical events is history, and rocks/geologic features is geology.

Answer:

The study of what matter is made of, how it's structured, and how it changes or reacts with other substances