Answer:
A.
Explanation:
Rainforests are forests characterized by high and continuous rainfall, with annual rainfall in the case of tropical rainforests between 2.5 and 4.5 meters and definitions varying by region for temperate rainforests.
Most rainforests are structured in four layers: emergent, canopy, understory, and forest floor.
Emergent Layer
The top layer of the rainforest is the emergent layer. Here, trees as tall as 60 meters (200 feet) dominate the skyline. Foliage is often sparse on tree trunks, but spreads wide as the trees reach the sunny upper layer, where they photosynthesize the sun’s rays. Small, waxy leaves help trees in the emergent layer retain water during long droughts or dry seasons. Lightweight seeds are carried away from the parent plant by strong winds.
Canopy Layer
Beneath the emergent layer is the canopy, a deep layer of vegetation roughly 6 meters (20 feet) thick. The canopy’s dense network of leaves and branches forms a roof over the two remaining layers.
Understory Layer
Located several meters below the canopy, the understory is an even darker, stiller, and more humid environment. Plants here, such as palms and philodendrons, are much shorter and have larger leaves than plants that dominate the canopy. Understory plants’ large leaves catch the minimal sunlight reaching beyond the dense canopy.
Forest Floor Layer
The forest floor is the darkest of all rainforest layers, making it extremely difficult for plants to grow. Leaves that fall to the forest floor decay quickly.
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