Approximately elements occur naturally on earth.

the answer to your question is c.

if you read the house of usher you should know that the house was haunted

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: