Soil

Which of the following is NOT one of the three layers of soil?

• topsoil
• undersoil
• subsoil
• bedrock

Which of the following is NOT one of the three types of soil?

• clay
• sand
• silt
• mud

_______ is the type of soil used most often with plants. It is a mixture of clay, sand, and silt.

• loam
• humus
• mud
• dirt

Humus is.....

• the dead parts of plants and animals in soil.
• A food we eat with pretzels.
• The tiny particles inside of soil
• The roots that come off of a plant and live in soil.

When there are not enough plants to hold topsoil in place, water and  _______ carry the topsoil away, leaving the subsoil exposed

• sunlight
• birds
• magnetic fields
• wind

When plants, animals, and other organisms die, they break down and become part of the soil. What is this part of the soil called?

• sand
• silt
• clay
• humus

Which of the following is the largest particle in soil?

• sand
• silt
• humus
• clay

Many plants cannot grow in sandy soil. Why is this true?

• Sandy soil does not hold enough water.
• Oxygen cannot pass through sandy soil.
• Roots cannot easily push through clay soil.
• Sandy soil has too many nutrients.

Which layer of soil are these roots growing in?

• subsoil
• topsoil

Wind blowing dirt and sand through the air is an example of...

• weathering 
• erosion