1.why were these seven plates considered as the major plates?2-3sentences 2.what is the importance of identifying the major plates?2-3sentence

Due to their large size.

Explanation:

Seven plates considered as the major plates on the earth because of their large size. African, Antarctic, Eurasian, Indo-Australian, North American, Pacific and South American plates are the seven major plates present on the earth. The importance of identifying the major plates is that they provide information about the location of happenings earthquakes and volcanic eruption.