Africa is described as the most tropical continent because

Step 1: Analyze the question The question asks why Africa is called "the most tropical continent." The key word is tropical, which relates to the Tropics, the zone between the Tropic of Cancer (23½°N) and the Tropic of Capricorn (23½°S).

Step 2: Explain the concept The Tropics are the region on either side of the Equator, bounded by the two tropic lines. A continent is described as "tropical" based on how much of its land lies within this zone.

• The Equator runs through the middle of Africa.
• The Tropic of Cancer crosses the Sahara in the north (through Algeria, Libya and Egypt).
• The Tropic of Capricorn crosses the south (through Namibia, Botswana, South Africa and Madagascar).
• Africa extends from about 37°N to 35°S, so the large majority of its land falls between these two lines.

Step 3: Evaluate each option

• A. Most parts of Africa lie within the tropics. This is correct. It directly explains why Africa is called the most tropical continent.
• B. It lies astride the Greenwich Meridian. This concerns longitude (0°) and has nothing to do with climate or the tropics. Wrong.
• C. Free movement of people in the sub-region. This is political and social, not geographical. Wrong.
• D. It nears the poles. Africa is far from the poles. Being close to the poles would make a place cold, not tropical. Wrong.

Step 4: Answer The correct option is A: most of Africa lies within the tropics.

Exam tip: "Tropical" means "between the Tropic of Cancer and Tropic of Capricorn." Longitude (Greenwich Meridian) tells you about east and west, while latitude (the Tropics) tells you about climate zones. When a question mentions "tropical," look for the option about latitude or the tropics.