Final answer:
The least amount of air movement in tropical rainforests is found at the forest floor due to the dense vegetation, but the closest answer from the provided options is the third layer of the canopy.
Step-by-step explanation:
The student asked where the least amount of air movement in tropical rainforests is found. Tropical rainforests exhibit a vertical layering of vegetation and distinct habitats for animals within each layer. The structure of these biomes includes the undergrowth on the forest floor, an understory, the main canopy layer, and sometimes emergent trees that rise above the canopy.
In a tropical rainforest, the least amount of air movement is likely to be found at the forest floor, where the dense vegetation and the upper layers significantly reduce wind penetration.
However, the provided options do not include the forest floor, indicating a possible oversight in the question. But if we consider the three given layers of the canopy, the third layer of the canopy would typically experience less air movement than the more exposed upper layers. Therefore, the answer from the choices provided would be (c) third layer of the canopy.