What happens when the temperature of a substance decreases significantly? A. Most substances will disappear. B. Most substances will gain atoms. C. Most substances will contract.

The answer is C Most substances will contract. I know this because I just had it on a test and got it right

The answer is; C

The reason they contract is that as the substance loses heat, the atoms also lose their kinetic energy and stop vibrating or bombarding each other vigorously. The distance between the atoms, therefore, decrease and the substance consequently shrinks a bit.