They are made up of particles that are arranged in a repeating pattern.
The answer is gravity:
Explanation: an invisible force that pulls objects toward each other. Earth's gravity is what keeps you on the ground and what makes things fall. Anything that has mass also has gravity.
The term "pKa" is a measure of the strength of an acid in solution. It is defined as the negative base 10 log of the acid dissociation constant. A lower pKa value indicates a stronger acid and A higher pKa value indicates a weaker acid