Understanding Soil and Its Formation

What percentage of soil is composed of minerals?

• 95%

• 50%

• 45%

• 5%

Which layer of soil is rich in organic matter and is crucial for plant growth?

• Immature Soil

• Bedrock

• Substratum

• Topsoil

What is the primary composition of the Bedrock layer?

• Organic matter

• Water

• Air

• Minerals

How long does it take to form 2.5 cm of soil?

• 1000 years

• 500 years

• 2000 years

• 100 years

What is the process called that breaks down rocks into smaller pieces to form soil?

• Compaction

• Sedimentation

• Weathering

• Erosion

Which type of weathering involves the physical breaking of rocks?

• Thermal weathering

• Mechanical weathering

• Biological weathering

• Chemical weathering

How do plant roots contribute to the weathering of rocks?

• By releasing oxygen

• By absorbing minerals

• By wrapping around rocks and causing cracks

• By providing shade

What effect does acidic rain have on rocks?

• It strengthens them

• It causes them to expand

• It slowly erodes them

• It makes them more colorful

In the process of weathering, which direction do minerals move?

• They remain static

• Sideways

• Downward

• Upward

What is the source of organic matter in soil?

• Substratum

• Humus

• Water

• Bedrock