CHAPTER 5 TEST: The Good Earth

Weathering is a process that breaks down rocks to create soil. This process takes

• many years

• a few days

• several months

• six weeks

Answer explanation

Weathering is a gradual process that can take many years to break down rocks into soil. This long duration is necessary for the physical and chemical changes to occur, making 'many years' the correct choice.

A student planted sunflower plants in different components of soil. In which component of soil will the plant have the most nutrients?

• Clay

• Humus

• Sand

• Rock particles

Answer explanation

Humus is rich in organic matter and nutrients, making it the best component of soil for plant growth. It provides essential nutrients that sunflower plants need to thrive, unlike clay, sand, or rock particles.

These organisms need soil to-

• provide support for trees to grow

• give shade from the sun

• provide a habitat for them to live

• give small streams water they need to flow

Answer explanation

These organisms need soil to provide support for trees to grow and to offer a habitat for them to live. Soil is essential for anchoring trees and supplying nutrients, making it vital for their survival.

Which soil component consists of small grains of worn-down rock, has few nutrients, and does not hold water well?

• Parent Rock

• Clay

• Bedrock

• Sand

Answer explanation

Sand consists of small grains of worn-down rock, has low nutrient content, and does not retain water well, making it the correct choice for the soil component described.

Soil is important to people because it -

• creates new landscapes

• supports the growth of a lot of food

• can be replaced quickly

• changes components quickly

Answer explanation

Soil is crucial for supporting the growth of a lot of food, as it provides essential nutrients and a habitat for plants. This makes it vital for agriculture and food production, unlike the other options which are less relevant.

Which layer of soil is BEST for plant growth?

• Bedrock

• Subsoil

• Topsoil

• Parent Material

Answer explanation

Topsoil is the uppermost layer of soil, rich in organic matter and nutrients, making it the best for plant growth. It provides essential minerals and supports root development, unlike bedrock, subsoil, or parent material.

Based on your observations of this investigation, what conclusion can be made about how different types of soil affect plant growth?

• A. Clay has the most nutrients for plant growth.

• B. Plants grow better in rocks than in sand.

• C. Plants grow well in humus.

• D. Rock fragments produce the same growth as clay.

Answer explanation

Clay and humus are rich in nutrients, promoting better plant growth. Therefore, options A and C are correct, as they highlight the nutrient benefits of clay and humus for plants.

A student wants to plant a rose bush in the yard. Which might help the bush grow better?

• Adding organic matter or humus to the soil

• Replacing the removed soil from the hole with clay

• Adding rocks and sand to the soil

• Placing the roots of the bush on top of the ground

Answer explanation

Adding organic matter or humus improves soil structure, enhances nutrient availability, and promotes better water retention, all of which help the rose bush grow healthier compared to the other options.

Which component of soil holds the most water?

• Sand

• Bedrock

• Humus

• Clay

Answer explanation

Clay holds the most water among soil components due to its small particle size and high surface area, which allows it to retain moisture effectively. In contrast, sand has larger particles and drains quickly, while humus and bedrock do not retain water as well.