The vegetation of savannah consists of grassland with scattered small trees, but extensive areas have no trees. The forest development in such areas is generally kept in check by one or more or a combination of some conditions. Which of the following are such conditions? 1. Burrowing animals and termites 2. Fire 3. Grazing herbivores 4. Seasonal rainfall 5. Soil properties Select the correct answer using the code given below.

The UPSC-style item lists 'Burrowing animals & termites' alongside fire, grazing and seasonal rainfall as conditions that can keep forest development in check in savannahs.

A student could take this as a hypothesis to investigate locally (e.g., map termite/burrow density vs. tree recruitment) or look for field studies linking soil disturbance by these organisms to seedling mortality.

Explains that burrowing organisms (earthworms, termites, rodents) actively alter soils by exposing surfaces, changing moisture and aeration — a general mechanism by which they can affect plant establishment.

One could extend this by reasoning that soil disturbance and altered moisture regimes might reduce seed survival or root establishment for tree seedlings in savannahs.

Gives a pattern: fires, large herds trampling seedlings, and seasonal drought are recognised mechanisms that prevent forest development in savannahs — showing the class of biotic/abiotic processes that limit tree establishment.

Use this pattern to compare with burrowing/termite activity (another biotic process) to assess plausibility that they could play a similar limiting role.

States that savannahs result from factors like frequent fires and overgrazing and that they include treeless tracts — supporting the general idea that multiple disturbance agents maintain treeless conditions.

Combine this with the notion that termites/burrowers are disturbance agents to justify field checks (e.g., whether areas with intense termite activity coincide with reduced tree cover).