In india, a system of stratification persists, partially because it was exploited by british colonialism to persistently divide the people. this division of society into four main groups (brahaman, kshathriya, vaishyas, and shudra) is an example of

Verna system divides the Indian Society into Brahman, Kshatriya, Vaishyas, and Shudras which was originated during Vedic System, however, the three societies Brahman Kshatriya and Vaishyas gain inheritance with other Indo-European Societies whereas Shudras was added by Brahmans from northern India and division of society according to Verna system was highly prevalent during colonialism which played key role in division of population

the earth’s crust is broken into separate pieces called tectonic plates (fig. 7.14). recall that the crust is the solid, rocky, outer shell of the planet. it is composed of two distinctly different types of material: the less-dense continental crust and the more-dense oceanic crust. both types of crust rest atop solid, upper mantle material. the upper mantle, in turn, floats on a denser layer of lower mantle that is much like thick molten tar.

each tectonic plate is free-floating and can move independently. earthquakes and volcanoes are the direct result of the movement of tectonic plates at fault lines. the term fault is used to describe the boundary between tectonic plates. most of the earthquakes and volcanoes around the pacific ocean basin—a pattern known as the “ring of fire”—are due to the movement of tectonic plates in this region. other observable results of short-term plate movement include the gradual widening of the great rift lakes in eastern africa and the rising of the himalayan mountain range. the motion of plates can be described in four general patterns:

collision: when two continental plates are shoved together

subduction: when one plate plunges beneath another (fig. 7.15)

spreading: when two plates are pushed apart (fig. 7.15)

transform faulting: when two plates slide past each other (fig. 7.15)