The chemical reactions done by living organisms are known as

chemical reaction done by living organisms is called biochemical reactions. the sum of all the biochemical reactions in organism is called metabolism.

Metabolism

Explanation:

Metabolism is the chemical reaction done by living organisms.

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:

it is the most commonly accepted one