Final answer:
The source of parent material for soil is rock pieces, which undergo weathering and break down over time. Bacteria, algae, and the decomposition of organic matter also contribute to soil formation.
Step-by-step explanation:
The source of parent material for soil is rock pieces. These rock pieces undergo weathering and break down over time to form the mineral content of the soil. Bacteria and algae also contribute to the formation of soil, but they are not the primary source of parent material. The decomposition of organic matter such as dead plants and animals also adds nutrients to the soil.
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