Answer:
They can be used for food and resources.
Explanation:
The answer would be crystals
Hey there!
Airplanes must be pressurized when flying at high altitudes so that the oxygen levels stay normal for us to breathe. The higher you go up, the thinner the air gets, which causes breathing problems for us humans.
Thank you!
Answer:
C
Explanation:
Roads can vary in elevation, since a road is essentially any path to walk on.
Hills have varying elevations - they are higher at certain points.
Rivers can flow downhill and aren't always at equal elevation.
Contour lines on a topographical map connect points of equal elevation. If you were to follow a contour line while walking, the elevation would remain constant.