A tropical rainforest typically has four distinct layers: the emergent layer, canopy, understory, and forest floor. These strata divide the forest vertically, with different light levels, temperatures, plants, and animals in each.
The emergent layer contains a small number of the tallest trees, often rising above the main roof of foliage. Beneath it, the canopy forms a nearly continuous leafy ceiling and supports an enormous share of rainforest life, including birds, monkeys, insects, orchids, and bromeliads. The shaded understory contains smaller trees, shrubs, vines, reptiles, and many insects.
At the bottom, the forest floor receives very little sunlight. Fallen leaves and dead organisms decompose rapidly in the warm, humid conditions, allowing nutrients to be recycled quickly. Despite the forest’s lush appearance, its soil is often nutrient-poor because heavy rain leaches minerals away.
Some textbooks subdivide these zones further, adding a shrub layer or separating parts of the canopy. That is why counts of five or more sometimes appear, but the standard broad classification used in general quizzes is four.