Which is a major drawback to the use of ethanol-based energy?
a. the use of ethanol is only efficient near rivers.
b. ethanol creates toxic waste that must be stored forever.
c. burning ethanol releases greenhouse gases.
d. ethanol may run out in the next 100 years

Burning ethanol releases greenhouse gases. - c.

true. earthquakes are felt whenever there is a slip around a fault in the rocks below the earth. this reorientation of faults create sesmic waves and is known as earthquake, the severity of which is measured in richter scale. these are more prominent in hilly regions as the rocks usually form faults to balance the pressures on it.