Question

Which forest plants control light conditions at the ground?
A. Lianas and climbers
B. Shrubs
C. Tall trees
D. Herbs

Answer 1

Hint: Tropical rain forests are very thick and nearly impenetrable.
The climate is warm and moist, and there are almost no seasonal variations.
The sunlight is strong but very little light reaches the ground through the dense foliage.

Complete answer: Dense evergreen trees with broad leaves form the dominant vegetation.
The trees are of various height, and distinct stratification can be recognized.
The tallest trees (50-100m. high) form a nearly continuous canopy at the top.
The tallest trees are of the tropical evergreen forests are the emergent layers. Most of the trees are broad-leaved.

Additional information: Factors of controlling light conditions at the ground:
1. The temperature is high and fairly constant.
2. The soil is rich in minerals and humus as the high temperature and moisture are favorable for the decomposition of fallen leaves and dead organic matter by the decomposers.
3. Many types of epiphytes and woody climbers (lianes) grow on the trees to reach light for food making. The epiphytes are also called air plants.
4. They have aerial roots to absorb water and trap falling leaves and other organic debris as a source of nutrients. Epiphytes include orchids, bromeliads, and ferns.
5. There is sparse herbaceous vegetation on the floor, and actual bare spots occur in certain areas.

So the correct answer is C. Tall trees

Note: The tall trees of the emergent layer being broad-leafed and with that canopy control light condition at the ground.