The social groups that he mentions are Hindus and Muslims. Yes, these groups were easily identifiable by their dressing, tradition, culture, etc. For instance, Kalam used to wear a cap on his head which identified him as a Muslim. Ramanadha Sastry wore a sacred thread.
(i) The kind of person the doctor is (money, possessions)
(ii) The kind of person he wants to be (appearance, ambition)
∆ABC is an isosceles triangle in which AB = AC. Side BA is produced to D such that AD = AB (see Fig. 7.34). Show that ∠ BCD is a right angle.