What causes a spring to bounce up when it is pushed down and then released?
(a) Pushing the spring down gives it stored mechanical energy that turns into motion (b)The stored chemical energy in the spring turns into motion. (c) The chemical energy in the spring makes it move and bounce up. (d) Pushing the spring downturns chemical energy into mechanical energy.

(a) Pushing the spring down gives it stored mechanical energy that turns into motion

Explanation:

Pushing on the spring causes the mechanical energy, of pushing on the spring, to be stored in the spring through potential elastic energy. Due to the elasticity of the spring, when the spring is released and resumes its initial shape the stored energy is released and can be used to do work such as motion.

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: