Answer to Question 1
It is an interbreeding population whose members share a greater number of traits with
one another than they do with people outside the group.
Answer to Question 2
Caste membership is directly related to occupation, workloads, and control of
resources; members of the same caste share the same social status; each caste has its
own set of secret rituals; and higher castes are most interested in maintaining the
system because they benefit from it the most.