The first migration of humans around the globe was related to:

A the need to find sites for towns.

B the search for iron.

C population pressure.

D the food supply.

the correct answer is D

it was related to the food supply

The early humans moved out Africa when the climatic condition in the region of East Africa Rift valley, where earliest stone tools were discovered became increasingly dry. Hunting as a source of food also became scarce as animals also spread out of the region. Subsequent strains in areas where they conquered led them to migrate further across the globe.