Which best explains a primary reason for the inability of life to exist in Earth’s early atmosphere? A. There was insufficient energy from material collisions to change their density.
B. High temperatures during Precambrian time caused surface water evaporation. C. Volcanic eruptions and comet collisions added different gases to the atmosphere D. Available oxygen was used to help create an ozone layer within Earth’s atmosphere.
FAST PL >_

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.

in cartography, a contour line (often just called a "contour") joins points of equal elevation (height) above a given level, such as mean sea level. a contour map is a map illustrated with contour lines, for example a topographic map, which thus shows valleys and hills, and the steepness or gentleness of slopes.

explanation:

they are both synthetic elements

explanation:

d