Answer:
light
Explanation:
it's a process call photosynthesis in which light is converted into nutrients
Layers of the soil are called horizons. Here are the horizons:
- Humus
- Topsoil
- Subsoil
- Fragmented rock
- Bedrock
Once a soil has developed, it forms layers called horizons. Beneath a surface layer of a plant remains, the topsoil is rich in decomposed plants and animal matter. The subsoil is mainly mineral particles, with much less organic material. The fragmented rock/bedrock is primarily small stones, and beneath it lies all bedrock.
Hope this answer helps you!
A biome is defined as the large ecological area where the formation of plants and animals with common characteristics gather due to the similar climates. If I were an ecologist, and i will be determining whether an entire river and lake biome is being threatened by human activity, the indicator species that i might look for are the ones that have been introduced into the biome.