1. The agent of mechanical weathering in which rock is worn away by the grinding action of other rock particles is called: a. erosion b. cracking and peeling c. abrasion

2. Ice wedging causes mechanical weathering of rock by means of
Heating and cooling
Plant growth
Freezing and thawing of water

3. A rock containing iron becomes rusty
A rock containing iron becomes rusty. It probably has been weathered by:
Abrasion
Carbon dioxide
Oxygen

4. Carbon dioxide and acid rain Abrasion and acids from plants
The most important factors in determining how fast a rock will weather are:
Carbon dioxide and acid rain
Abrasion and acids from plants
Rock type and climate

5. Living organisms in the soil help to: Slow the rate of soil formation
Build up bedrock
Mix the soil to make humus

6. Decomposers are the soil organisms that Store moisture in the soil
Break down and digest the remains of dead organisms
Make spaces in the soil for air and water

7. Soil is a valuable resource because it
Is important to all living things on land
Contains sand and gravel
Is rich in decomposers

8. It reduced the soil’s fertility. It helped cause the Dust Bowl
Plowing removed the grass from the Great Plains and exposed the soil. What effect did this have when a drought struck the Great Plains during the 1930’s?
It had no effect.
It reduced the soil’s fertility.
It helped cause the Dust Bowl

9. Most of the work of mixing humus within the soil is done by:
Fungi
Ants
Earthworms

10. The mountains have been eroding for millions of years.
Geologists infer from the rounded, eroded shapes of the Appalachain Mts. that
The mountains have been eroding for millions of years.
The principal of uniformitarianism does not apply.
The mountains are made of soft rock.

11. True or False
The movement of rock particles by ice, wind, water, or gravity is called weathering.

12. True or False
The practice of preventing soil from being destroyed is called soil conservation.