Exogamy is a social practice where individuals are required to marry outside of their own social unit, such as their kin group or community. It is a form of marriage rule that promotes social integration and prevents incestuous relationships within a particular group.

Explanation:

Definition of Exogamy:
Exogamy refers to the practice of marrying outside of one's own social unit, typically based on kinship or community ties. It is a common marriage rule found in many societies around the world.

Options:
a) It is found only in the Himalayan region
b) Marriage takes place outside the village area
c) Marriage is with the same kin group
d) It is marriage outside the unit

Correct Answer:
The correct option is 'D' - It is marriage outside the unit.

Explanation:
- Option 'A' is incorrect because exogamy is not limited to the Himalayan region. It is found in various societies globally.
- Option 'B' is incorrect because exogamy does not necessarily imply marriage outside of the village area. It can extend beyond the village to a larger social unit.
- Option 'C' is incorrect because exogamy involves marrying outside of the kin group, not within the same kin group.
- Option 'D' is correct because exogamy involves marrying outside of the unit, which can refer to the kin group, community, or any other defined social unit.

Significance of Exogamy:
- Exogamy plays a crucial role in promoting social integration and preventing inbreeding within a particular group.
- It facilitates the exchange of individuals, resources, and alliances between different social units, fostering social cohesion and cooperation.
- Exogamous marriages help in the formation of social networks and connections between different communities, promoting cultural diversity and intergroup relationships.
- It also helps in maintaining social balance and reducing the risks of conflicts arising from competition within a limited pool of potential marriage partners.
- Exogamy can also contribute to the spread of cultural practices, ideas, and genetic diversity among populations.

Conclusion:
Exogamy is a marriage rule that requires individuals to marry outside of their social unit. It is not limited to the Himalayan region, but rather, it is a widespread practice found in many societies worldwide. Exogamy promotes social integration, prevents inbreeding, and facilitates the exchange of individuals and resources between different social units.