How do scientists know that dark matter exists? A) It’s heat raises the temperature of space.

B) Its gravity affects objects around it.

C) It gives off electromagnetic waves.

D) All of these.

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.