Unit 3 Review

Which layer has the most humus?

• Topsoil

• subsoil

• bedrock

• Clay

What happens when living things decompose?

• They grow healthy and strong

• they have babies

• they store up for winter

• their parts break down into the soil

What is the top layer of the soil?

• topsoil

• subsoil

• bedrock

• humus

Which part of the soil has bits of dead plants and animals?

• humus

• clay

• bedrock

What is the process of breaking down of organic matter in soil called?

• Decomposition

• Respiration

• Transpiration

• Condensation

What is the layer of soil beneath the topsoil called?

• Subsoil

• Bedrock

• Humus

• Clay

Which layer of soil is rich in minerals and nutrients?

• Topsoil

• Subsoil

• Bedrock

• Humus

What is the bottommost layer of the soil called?

• Topsoil

• Subsoil

• Bedrock

• Humus

What is the process of turning dead organic material into humus called?

• Decomposition

• Respiration

• Transpiration

• Condensation

Which layer of soil is least fertile?

• Topsoil

• Subsoil

• Bedrock

• Humus