Increasing or decreasing volume of a gas. what happens to the pressure? is this a direct or indirect relationship?

Inverse relationship.

Explanation:

P1V1 = P1V2

Increasing of volume - decreasing of pressure (particles of gas become farther from each other). Inverse relationship.

indicate valleys, hills, steepness and gentleness of slopes.

explanation:

contour lines on a map indicate elevation, or depth. numeric notations on contour lines refer to the level of elevation, or height about sea level.