What is exothermic and endothermic? how do they differ?

In the 1800s, one of the statements in john dalton's atomic theory was that atoms are indivisible. later experimental evidence led to the discovery of subatomic particles such as neutrons, electrons, and protons. what happened to the indivisible atom part of dalton's atomic theory, and why?

This drawing shows a human body system. what is the primary function of this body system?

The formation of a solid, also known as a is an indication of a chemical change. precipitate particulate particle powder