Geography entrance exam, 2012 E.C. (2020)

North Africa is mostly Sahara, so people crowd into the few places with water. Libya covers about 1.76 million square kilometres but holds only around 7 million people, which works out at roughly 4 people per square kilometre, the thinnest spread in the region.

Egypt is the tempting answer because its desert looks empty, but almost all Egyptians are packed along the Nile valley and delta, so the country as a whole is far more crowded than Libya.

Textbook: Geography Grade 10, Unit 4 Population of Africa, section 4.4 Distribution and density of Africa's population (page 105).

Infant mortality is the number of babies who die before their first birthday per 1,000 live births. In the 2020 figures, Central Africa had the highest rate in the continent at 62 per 1,000, followed by Western Africa at 55.

Northern Africa is the lowest at 22 per 1,000, so option C is the opposite of the answer. Central Africa's rate stays high because of conflict, weak health services and poor sanitation.

Textbook: Geography Grade 10, Unit 4 Population of Africa, section 4.2 Africa's major demographic trends, Table 4.6 (page 97).

Africa's median age was about 19.7 years in 2020, while Europe's was 42.5 years. A low median age means half the people are still children or teenagers, so the continent is dominated by the young age group.

Option A fails because Africa's crude death rate is not the lowest in the world; it is about 8 per 1,000, the same as the world figure and higher than in several richer regions. High fertility, not migration, is what keeps the African population young.

Textbook: Geography Grade 10, Unit 4 Population of Africa, section 4.3 Population structure.

Sex ratio counts males for every 100 females. A ratio below 100 means men are missing from the population. In sub-Saharan Africa civil wars kill mostly men, and it is mostly young men who leave to work in other countries, so the male side of the pyramid is thinned out.

Option D is the trap. Everywhere in the world slightly more boys are born than girls, about 105 boys per 100 girls, so births cannot explain a shortage of males.

Textbook: Geography Grade 10, Unit 4 Population of Africa, section 4.3 Population structure.

The people in the question leave for one working season and then go home again. Movement that lasts only a short time and ends with a return to the place of origin is temporary migration, and the seasonal farm labour described here is its classic example.

Permanent migration is ruled out because the workers come back. International and intra-continental migration are ruled out too, because the move stays inside one country.

Textbook: Geography Grade 10, Unit 7 Geographic Issues and Public Concerns in Africa, section 7.2 Migration, factors and impacts on Africa (page 157).

The losing country is the one people leave. It pays for raising, feeding and schooling young adults and then loses them at the very age when they would start working, which is why the loss of the productive age group, often called brain drain, is the main cost.

The other three options describe crowding, service costs and pressure on public facilities. Those are burdens on the country that receives migrants, not on the one that loses them.

Textbook: Geography Grade 10, Unit 7 Geographic Issues and Public Concerns in Africa, section 7.2 Migration, factors and impacts on Africa (page 157).