The correct option is (b).
Explanation
The Amazon Basin is characterized by tropical evergreen forests, often referred to as "selvas." These forests exhibit distinct stratification and dense vegetation patterns dictated by climatic conditions such as high temperature and heavy rainfall.
- Statement 1 is Incorrect: The forests in the Amazon Basin are extremely dense, not sparse. The trees form a thick, continuous roof-like structure known as the canopy. This dense canopy intercepts the majority of sunlight, preventing it from reaching the forest floor. Consequently, the interior of the forest remains dark and damp even during the day.
- Statement 2 is Correct: Due to the dense canopy blocking sunlight, the ground layer receives very little light. Therefore, only vegetation that is shade-tolerant can survive and grow on the forest floor. The lack of sunlight inhibits the growth of dense undergrowth in many parts, making the ground relatively clear unless the canopy is broken.
- Statement 3 is Incorrect: Orchids and bromeliads are characteristic plants of these forests, but they grow as epiphytes, not parasites. Epiphytes grow on other plants (trees) merely for physical support to access sunlight and moisture from the air; they do not derive nutrients from the host plant. Parasitic plants, in contrast, extract nutrients from the host.
Key Takeaway: Tropical rainforests are defined by a dense canopy that limits ground-level sunlight, necessitating shade-tolerant ground vegetation. Plants like orchids and bromeliads in these regions are epiphytes (commensalism), distinct from parasitic plants.