Determine the difference in elevation between one contour line and the next contour line on the
topographic map.

Lighter contour lines do not have elevations, but can be determined by counting up or down from the nearest index contour line and multiplying by the contour interval. The contour interval is stated on every topographic map and is usually located below the scale.

Explanation:

coal is not sustainable because it will one day run out.

succession returns a disturbed

ecosystem to a more stable state. this is also classified into two (2) types:

primary succession and secondary succession. the primary succession arises when

a new land is transformed and a bare rock has been exposed providing an environment

that can be occupied for the first time. while, secondary succession occurs

when a previously occupied environment was disturbed that kills much of all its

community

explanation: