U2 L5 soil formation

Leaves release acids into the soil as they decay.  How could decaying leaves affect rock in the soil beneath them?

• They could expose the rock to wind and water.
• They could decrease the amount of weathering that occurs within the soil.
• They could increase the amount of chemical weathering of rock and soil formation.
• They could decrease the amount of chemical weathering and slow down the rate of soil formation.

Granite has only recently been exposed at a location on Earth's surface.  How will this most likely affect the soil that will eventually form at this location?

• The soil will have a thick layer of humus in the A horizon.
• The soil will contain many of the same minerals as the granite has.
• The soil will consist of thin horizons compared to other types of soils.
• the soil will be made of mostly rock material instead of organic matter.

Which of the following is the source of humus found in soil?

• bedrock
• B horizon
• parent rock
• plants and animals

Soil begins to form when the process of ______________ breaks down parent rock.

• weathering
• soil horizons
• topography
• deposition

A distinct layer of soil is a 

• soil horizon
• soil profile
• humus
• topography

A vertical section of soil that shows the horizons is a 

• soil horizon
• soil profile
• humus
• parent rock

The A soil horizon contains 

• humus
• leached materials and little to no humus
• partially weathered parent rock

The B soil horizon contains

• humus
• leached materials and little to no humus
• partially weathered parent rock

The C soil horizon contains

• humus
• leached materials and little to no humus
• partially weathered parent rock

Soil particles are classified as 

• parent rock, humus and bacteria
• sand, silt and clay
• A horizon, B horizon and C horizon
• igneous, sedimentary and metamorphic