Why did Great Britain take over South Africa? (For Gold) but why?

because they wanted black British people

The British wanted to control South Africa because it was one of the trade routes to India. However, when gold and diamonds were discovered in the 1860s-1880s their interest in the region increased. This brought them into conflict with the Boers. ... Tensions between Boers and British led to the Boer War of 1899-1902

necessary and proper clause. the congress shall have power to all laws which shall be necessary and proper for carrying into execution the foregoing powers, and all other powers vested by this constitution in the government of the united states, or in any department or officer thereof.

d. islands off the coast of newfoundland