Low annual rainfall, sparse vegetation , high diurnal temperatures and cold nights are characteristic features of the?

Analyze the question: We need the biome (ecological zone) with four features: low annual rainfall, sparse vegetation, very high daytime temperatures, and cold nights.

Explain the concept: Temperature and rainfall decide the vegetation of a biome. Dry places have little water and few plants. With little vegetation and little cloud cover or humidity, heat escapes quickly after sunset. This causes a large diurnal (daily) temperature range: very hot by day, cold at night.

Solution: check each option

• A. Tropical rainforest: Has high rainfall, dense vegetation, and fairly constant warm, humid temperatures. This does not match.
• B. Desert: Has very low rainfall (often under 250 mm a year), sparse vegetation (cacti, xerophytes), scorching days, and cold nights because the dry air and bare ground lose heat fast. This matches all four features.
• C. Montane forest: Found in highland areas. It has cool temperatures and moderate to high rainfall, with fairly dense vegetation. This does not match.
• D. Guinea savanna: Has moderate rainfall, a distinct wet and dry season, and tall grasses with scattered trees. The vegetation is not sparse, and nights are not especially cold. This does not match.

**Answer: B. Desert.

Tip: Link "wide temperature range between day and night" with "dry air and little vegetation" and you will think of desert. In Nigeria, the far north, close to the Sahel and Sahara, shows this pattern most strongly in the harmattan season.