Explanation:

• Caste: A social hierarchy common in South Asian societies, characterized by hereditary classes with specific social roles. It is differentiated, not homogeneous.

• Tribe: Often a homogeneous, undifferentiated group with shared customs and territory, and a common ethos. Tribes exist as a total social entity.

• Varna: A broader Hindu social system of classes, with duties, rights, and social conduct, which is more differentiated than tribal setups.

• Peasantry: Refers to the class of rural, agrarian workers. It’s not a specific ethnic group and doesn’t necessarily have a common ethos or operate as a totality.