Changing Environments

Question 1

Which pair shows one natural environmental change and one change caused by people?

Accepted Answer

A sudden frost that kills some seedlings, and a construction crew clearing part of the meadow for a playground.

Answer

A farmer spraying pesticide on the meadow, and a nearby factory releasing smoke into the air.

Answer

A wildfire started by lightning, and a beaver building a dam in a nearby stream.

Answer

A rainstorm that waters the meadow, and a squirrel storing nuts in the grass.

Question 2

A new road was built through a forest, making it harder for squirrels to travel between the two sides. Some squirrels are not finding enough food. A park ranger suggests planting a line of trees along the road so squirrels can climb over it. Which statement best explains why this solution is a good idea?

Accepted Answer

The trees give squirrels a place to cross the road, so they can reach food on both sides.

Answer

The trees will attract more birds, which will eat the squirrels' food.

Answer

The trees will make the forest look prettier, but they do not help squirrels find food.

Answer

The trees will block the road, stopping cars from driving through the forest.

Question 3

A mountain stream that usually flows 4 m wide and 30 cm deep suddenly became only 10 cm deep in one week after a new dam reduced the water. The stream’s trout lay their eggs on the streambed each spring. Why are many of the trout eggs most likely to die because of this rapid change?

Accepted Answer

The eggs need to stay covered by water; the quick drop leaves them exposed, so they dry out before they can hatch.

Answer

The colder water temperature will protect the eggs even if they are out of the water.

Answer

The trout can quickly move the eggs to deeper pools later, so the eggs will be safe.

Answer

With less water, the eggs will grow faster and hatch sooner, helping them survive.

Try three questions

Which pair shows one natural environmental change and one change caused by people?

A mountain stream that usually flows 4 m wide and 30 cm deep suddenly became only 10 cm deep in one week after a new dam reduced the water. The stream’s trout lay their eggs on the streambed each spring. Why are many of the trout eggs most likely to die because of this rapid change?

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