Millet , sorghum, maize and onions are common crops growth in Nigeria in the

Analyze the question: It asks which vegetation zone in Nigeria is known for growing millet, sorghum (guinea corn), maize and onions.

Explain the concept: Nigeria's vegetation zones run from south to north, and rainfall decreases as you move north:

• Tropical rainforest (south): heavy rainfall, so crops like cocoa, oil palm, rubber, yam and cassava.
• Guinea savanna (middle belt): yam, maize, rice, sorghum.
• Sudan savanna (north): moderate-to-low rainfall with a long dry season, so cereals and drought-tolerant crops like millet, sorghum, maize, groundnut, cotton and onions (Kano, Sokoto, Katsina and Kebbi areas).
• Sahel savanna (far north-east/north): very little rainfall, semi-arid, and mostly suited to grazing and a limited amount of drought-resistant millet.
• Montane forest: highland areas such as the Jos Plateau and Mambilla, which suit temperate crops and grazing.

Solution:

1. Millet, sorghum, maize and onions need moderate rainfall and a distinct dry season.
2. Tropical rainforest is too wet, and montane forest is a highland area, so neither fits.
3. The Sahel is too dry for most of these, particularly maize and onions, apart from a little millet.
4. The Sudan savanna is the zone where all four are commonly grown, with onions famously produced in Sokoto, Kebbi and Kano.

Correct answer: B. Sudan savanna

Tip: Remember the pattern "Sudan = cereals + onions" (millet, guinea corn, maize, onions, groundnut, cotton). The Sahel is mostly for livestock, and the rainforest is for tree crops. When an exam question lists cereals and onions, think Sudan savanna.