Question

describing soil profiles
match each soil horizon to the description of its formation.
horizon c
horizon a
horizon b
horizon o
parent material barely affected by soil
formation process
accumulation of organic material
undergoes the most change, barely
resembles parent material
decomposed organic material mixes with
highly weathered parent material

Explanation:

• Horizon C: This is the layer closest to the bedrock (parent material). It has not been significantly altered by soil - forming processes like weathering and organic matter addition.
• Horizon A: Also known as the topsoil. It contains decomposed plant and animal matter (organic material) that has mixed with the weathered parent material from below.
• Horizon B: The subsoil. It has received materials (such as clay, iron oxides) that have been leached (moved down) from the upper horizons. It has undergone chemical and physical changes and no longer closely resembles the original parent material.
• Horizon O: The organic layer. It is composed mainly of accumulated plant litter (leaves, branches etc.) and other organic debris that has not yet been fully decomposed.

Answer:

horizon C: parent material barely affected by soil formation process
horizon A: decomposed organic material mixes with highly weathered parent material
horizon B: undergoes the most change, barely resembles parent material
horizon O: accumulation of organic material