Question

how long have people studied chemistry?
a. since fire was discovered
b. since gravity was discovered
c. since chemicals were discovered
d. since the atom was discovered

Explanation:

The study of chemistry has ancient roots. The discovery of fire was a significant event as early humans began to observe and utilize chemical - like changes (such as combustion). Gravity is a concept in physics. The discovery of chemicals as a distinct category and the discovery of the atom are more recent in the timeline of human knowledge compared to the discovery of fire.

Answer:

A. Since fire was discovered