Final answer:
Savannas do not develop into forests because of the limited rainfall and extensive dry season, which lead to conditions that favor grasses over trees and frequent fires that inhibit forest growth. Option B) Limited rainfall is the correct answer.
Step-by-step explanation:
Savannas do not develop into forests primarily due to limited rainfall and an extensive dry season which make conditions unfavorable for dense forest growth. Unlike tropical rainforests which have a vertical layering of vegetation, savannas are comprised of wide, open grasslands with scattered trees.
The dry season in savanna biomes leads to conditions that are conducive to fires, which further inhibit the growth of forest trees. Additionally, savanna vegetation, particularly grasses with the C4 photosynthetic pathway, is highly adapted to hot, dry climates, and low concentrations of atmospheric CO₂, providing them with a competitive edge over woody vegetation. This adaptation includes well-developed root systems that allow plants to quickly recover and re-sprout after fires.
The presence of an extensive dry season and consequent fires results in savannas having relatively few trees compared to rainforests, which have a continuous wet climate that supports their dense canopy. Therefore, based on the information provided, the correct answer to why savannas do not develop forests is B) Limited rainfall.