Weathering and Soil Formation

The agent of mechanical weathering in which rock is worn away by the grinding action of other small rock particles is called ___.

• erosion

• cracking and peeling

• abrasion

• ice wedging

A rock containing Iron becomes soft, crumbly, and reddish-brown in color. It probably has been chemically weathered by a reaction with ___.

• abrasion

• acid rain

• oxygen

• plants

The growth of plant roots and animal activity are examples of ___.

• mechanical weathering

• erosion

• chemical weathering

• abrasion

A marble statue is left exposed to the weather. Within a few years, the details carved on the statue have begun to weather away. This weathering is probably caused by ___.

• oxidation

• acid rain

• lichens

• abrasion

Ice wedging causes mechanical weathering of rock by means of ___.

• heating and cooling of air

• plant root growth

• animal actions

• freezing and thawing of water

What type of weathering causes the mineral composition of rocks to change?

• chemical weathering

• general weathering

• mechanical weathering

• permeable weathering

Geologists infer from the rounded, eroded shapes of the tops of the Appalachian Mountains that ___.

• the mountains formed recently

• the mountains are made of soft rock

• the mountains are not being changed

• the mountains have been weathering and eroding for millions of years

The most important factors in determining the rate of weathering are ___.

• carbon dioxide and acid rain

• abrasion and acid from plant roots

• animal action and oxygen

• the type of rock and the climate of the area

Permeable rock weathers easily because it ___.

• is made up of small minerals

• is made of only one mineral

• contains many small, connected air spaces

• is made of no minerals

A hot, wet climate causes weathering to take place ___.

• slowly

• quickly

• unevenly

• at the same rate as a cool, dry climate