Minerals from several closely related species make up a

Group

Explanation:

A Group refers to the amalgamation of minerals from several closely related species. It is done for easier classification and is the third tier in Mineral classification with the first being the Variety of the Mineral, the second being the Species and the third being the Group.

An example of a group is Feldspar which is a group of tectosilicate minerals.

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.