Which of the following statements is true? Erosion can be reduced by planting trees and other plants.
Warm air is more denser than cold air.
It forms areas of high pressure.
Most of the earth's freshwater is located deep below the crust.
The most abundance gas in the atmosphere is oxygen.

erosion can be reduced by planting trees and other plants

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.

it's filtration, but this is an assumption so my apologies if i got this