The correct option is (c).
Explanation
The growth of vegetation depends primarily on temperature and moisture. The major vegetation types of the world are generally grouped as forests, grasslands, scrubs, and tundra. The amount of rainfall directly influences the density and size of the vegetation cover.
Statement 1 is Incorrect:
In areas of heavy rainfall, huge trees thrive rather than small shrubs. Forests are abundant in regions with plentiful water supply, leading to dense canopies and tall trees (e.g., Tropical Evergreen Forests). Small shrubs are not the dominant vegetation in high-rainfall zones.
Statement 2 is Correct:
As the amount of moisture decreases, the size of trees and their density reduces. In regions of moderate rainfall, short stunted trees and grasses grow, forming the grasslands of the world. This transition marks the shift from closed-canopy forests to open grasslands.
Statement 3 is Correct:
Thorny shrubs and scrubs grow in dry areas of low rainfall. In these regions, plants adapt to conserve water; they often possess deep roots to access groundwater and leaves with thorny or waxy surfaces to reduce moisture loss through transpiration.
Key Takeaway:
Vegetation density and height are directly proportional to precipitation levels: heavy rainfall supports dense forests, moderate rainfall supports grasslands, and low rainfall supports thorny scrubs.