Concept:Federalism is adopted in Nigeria mainly to manage its wide ethnic, religious, and linguistic diversity through a system that balances state autonomy with central authority.
Explanation:Nigeria is made up of many distinct ethnic, religious, and cultural groups with varying interests and needs.
Without an accommodating political framework, these differences could lead to tension or domination by one group.
A federal system allows each state to create and implement laws that address issues specific to its own region.
At the same time, a central government coordinates national policies and holds the country together.
This shared arrangement ensures that no single group feels suppressed while maintaining one sovereign nation.
Consequently, the fundamental reason behind Nigeria's federal structure is to achieve and preserve unity in diversity.
Answer:D. promote unity in diversity