Which substance can not be broken down by a chemical change? A)
magnesium
B)
water
C)
methane
D)
ammonia

a

Explanation:

its too much of a solid to be broken down

answer; /// i do believe that the correct answer is (a) boiling

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: