Concept:Bush burning can be harmful, but one useful effect is helping to clear the land before planting.
Explanation:Bush burning reduces soil microbial activities, exposes the soil to erosion, and lowers soil organic matter.
These are harmful effects, so they cannot be the beneficial result.
It also does not improve soil water holding capacity because organic matter is lost.
However, the heat from bush burning destroys weed seeds and some pests.
This reduces weed competition and helps the farmer prepare a cleaner seedbed.
Answer:C. destruction of weed seeds