A characteristic feature of tropical rainforest is that it

Analyze the question: The question asks for a characteristic feature of the tropical rainforest. We need to pick the option that correctly describes this vegetation zone.

Explain the concept: The tropical rainforest is found near the equator, in the southern parts of Nigeria (e.g., Ondo, Edo, Cross River). Its main features are:

• Very high rainfall, usually over 200 cm per year, spread across most of the year
• High temperature and humidity all year
• Very high biodiversity, with many different plant and animal species
• Tall trees forming a layered structure: emergent layer, canopy, understorey, and shrub layer
• Broad leaves, often with drip tips so heavy rain runs off quickly
• Dense canopy that blocks much sunlight, so the forest floor is dark

Solution (option by option):

• A. Narrow leaves: Wrong. Rainforest trees have broad leaves to capture light under the dense canopy and to carry out transpiration in humid conditions.
• B. Large number of plant species: Correct. Rainforests are the most species-rich terrestrial ecosystems. Warm, wet conditions all year allow many species to coexist.
• C. Fewer plant species: Wrong. This is the opposite of the truth. Fewer species is more typical of the savanna or temperate coniferous forests.
• D. Rainfall of less than 50 cm: Wrong. This describes a desert or semi-desert. Rainforests receive well over 150-200 cm annually.

Answer: The correct option is B.

Tip: Link "rainforest" with "rich": lots of rain, lots of species, lots of layers. If an option says "few species" or "low rainfall" for a rainforest, eliminate it immediately.