The sparse population in the middle belt of West Africa can be traced to all of the following except

The sparse population in the middle belt of West Africa can be traced to all of the following except the concentration of industries.

1. Inter-ethnic war: Conflict between different ethnic groups can cause displacement and hinder population growth in the affected areas. It leads to a disruption in the social fabric and discourages people from settling in these regions.

2. Tsetse fly infestation: The presence of tsetse flies, which are carriers of the sleeping sickness disease, can greatly affect human habitation. These flies are notorious for their bites which can transmit the disease to humans and livestock. The presence of tsetse flies in the middle belt of West Africa makes it difficult for people to inhabit the area due to health risks.

3. Arab slave trade in the North: The Arab slave trade, which took place predominantly in North Africa, resulted in the forced migration and enslavement of many African populations. This historic slave trade did not have a direct impact on the sparse population in the middle belt of West Africa.

4. Concentration of industries: The concentration of industries usually leads to urbanization and increased population in certain areas. This option does not contribute to the sparse population in the middle belt of West Africa.

Therefore, the correct answer is that the sparse population in the middle belt of West Africa cannot be traced to the concentration of industries.