Na m e : ___ Date: _
Directions:Topic sentence:
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_______________________________________________________________________________It happens when rock and soil break down in small pieces and then move down a hill, a
cliff, or a mountain. Erosion can be caused by natural forces such as wind, rain, or
temperature. This gradual wearing away of the earth can damage property, too. If your
home is built on a hill that is eroding, then the house may be in danger of sliding down
the hill, as well. Some people plant grass and trees on their
hillside land so that the plants’ strong root systems will hold the
earth in place. Other people lay a special netting over the soil.- Erosion causes a muddy mess.
- Erosion affects the earth and people.
- People have found ways to battle erosion.
Topic sentence:
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_______________________________________________________________________________This huge, gaping canyon in northwestern Arizona stretches across the land for 200 miles
and is more than 5,000 feet deep. The Colorado River formed this wonder of the world. Its
waters gradually cut the earth and stone away and downward to create a steep, carved
canyon. This did not happen overnight, however. The process
started about six million years ago.- The Grand Canyon is a National Park.
- There is no other place on Earth like the Grand Canyon.
- The Grand Canyon is a magnificent example of erosion.
Read the supporting details. Then, circle the number of the best topic sentence and
write it on the lines.You see, it’s just like math. Add up all supporting
details and you get the main idea, or topic.