Question

soil formation
three types of weathering
comprises mineral matter, organic matter, humus, air, and water.
humus, a jelly - like substance from decaying organic material, enriches
soil matter. soil is a dynamic ecosystem, hosting various living
organisms. from microorganisms to insects and mammals.

when breaking down soil components, mineral matter forms the largest
part, around 45%. air and water make up about 25% each, and organic
matter constitutes 5%, including humus and living organisms. this
combination of biotic and abiotic factors makes soil an ecosystem.

what contributes to the nature of soil as an ecosystem?

• the absence of living organisms
• combination of biotic and abiotic factors
• the lack of air and water in the soil

Explanation:

An ecosystem is composed of both biotic (living) and abiotic (non - living) factors. In the context of soil, the text mentions that soil has mineral matter (abiotic), organic matter (which can be from decomposed biotic sources), air, water (abiotic), and living organisms (biotic). The absence of living organisms would not make it an ecosystem as ecosystems require life. The lack of air and water also goes against the definition of an ecosystem as these are important abiotic components.

Answer:

combination of biotic and abiotic factors