47)
Sample Earthworms Humus(decomposed organic matter excreted by earthworms) Water retention Plant growth
1 Absent Absent Moderate Moderate
2 Present Rich in humus High High

William compared two soil samples to check soil’s ability to support the growth of plants. He had read that plants grow best in soil rich in humus. The experimental data is summarized in the table.

What conclusion can be BEST drawn from the data?
A) Soils rich in humus improve plant growth.
B) Earthworms do not improve the soil’s humus content.
C) Plants will not grow in soils that do not have earthworms.
D) The growth of plants is poor in soil that has decomposed organic matter.