Low population densities of the middle belt of West African countries can best be described as

Analyzing the question

The question asks about the low population density of the Middle Belt of West African countries (e.g., Nigeria's Middle Belt, Ghana's middle belt areas, Togo and Benin's central regions). The wording "can best be described as" is awkward. It really means "can best be explained by" or "is best attributed to". So we need the factor that would cause people to be sparse there.

Concept

Population density depends on factors that either attract people (fertile soil, industries, minerals, good climate) or reduce and repel them (slave raids, disease, war, poor soils).

Checking each option

• A. Trans-Saharan slave trade: Raiders and slave traders captured people from the Middle Belt, which lay between the savanna states and the forest or coast. Many people were carried off or fled to hills and remote areas. This depopulated the region over centuries. It also explains the historical emptiness often cited for the Middle Belt. This is a cause of low density.
• B. Rich fertile soil: This attracts settlement and raises density, so it does not explain low density.
• C. Concentration of industries: Industries draw people and create high density, as in Lagos or Kano. This is the opposite effect.
• D. Presence of mineral resources: Minerals such as tin on the Jos Plateau attract migrants and raise density. This is also the opposite effect.

Answer

Only option A is a factor that reduces population. Options B, C and D would increase density.

Exam tip: Whenever a question asks for a reason for low density, look for a negative or repelling factor such as slave trade, disease (tsetse fly, river blindness), war, or harsh climate. Eliminate options that attract people. Also, if a question's wording seems odd, rephrase it in your head (here: "what explains low density?") before you answer.