Each statement best explains why it is more difficult to use coal versus other alternate source of energy except: It is more difficult to mine for coal than other minerals.
Coal produces more pollutants in the air.
Coals are not commonly used because it is more difficult to burn.
Coals are not commonly used because it produces more negative impact to the environment.

$452.90 because you needed to round to the nearest cent

the diagram shows you   triangle def with de=4, df=9 and de≠df≠ef.

the sum of the lengths of two triangles' sides are always greater than the length of the third side:

substitute sides lengths:

then 5< ef< 13 (option 3 is true).

def is a scalene triangle with all sides of different lengths (option 5 is true, option 2 is false).

answer: correct choices are 1, 3 and 5