Question

what do chemists study to understand the interactions and transformations of substances?
a. stars and galaxies
b. mountains and rivers
c. atoms and molecules
d. computers and software

Explanation:

Chemistry focuses on the composition, properties, and changes of substances. Substances are made up of atoms and molecules, so studying these particles reveals how substances interact and transform. The other options relate to astronomy (stars/galaxies), geography (mountains/rivers), and computer science (computers/software), which are unrelated to chemical substance interactions.

Answer:

c. Atoms and molecules