Which of the following statements is correct in regards to density?
Temperature is directly proportional to density.
Temperature and pressure do not affect density.
Pressure is directly proportional to density.
Pressure is inversely proportional to density.

Pressure is directly proportional to the density of a substance.

Explanation:

Pressure is a measure of force per unit area. Density is defined as mass per unit volume i.e the ratio of mass of a substance to it's volume.

Thus, it means that an increase in pressure results in an increase in density and vice-versa.

gas

explanation:

smoke is the matter of a gas