更多"Why researchers put trees in extra "的相关试题:
[单项选择]Why researchers put trees in extra carbon dioxide in the first study
A. To learn whether trees can still absorb carbon dioxide under extreme conditions.
B. To get more oxygen from these trees.
C. To evaluate the maximum carbon dioxide that trees can absorb.
D. To see the growth rate of these trees.
[单项选择]Why did people cut down trees
A. For advantage.
B. For benefit.
C. For house.
D. For business.
[单项选择]Why did Shaefer put the paper under glass
A. To make things as difficult as possible.
B. To stop the reflection of heat.
C. To prevent Rose from feeling the print.
D. To stop her from cheating.
[单项选择]Why was it possible for these ancient trees let more light through than modern ones
A. Because they were closely spaced, only 3 to 16 feet apart.
B. Because they were smaller plants and shrubs.
C. Because their branches did not fan out as far as to form a shape like umbrella.
D. Because they had very small leaves like that of fern and dropped easily.
[单项选择]Why do some people think hemp is better than trees for paper industry
A. It is cheaper to grow hemp than to cut down trees.
B. More paper can be produced from the same area of land.
C. Hemp planting can beautify the environment.
D. Hemp can produce paper of high quality.
[单项选择]Why is the close planting of trees of the same species avoided in modern orchards and forests
A. Because mixed forests and orchards are the recognized procedures these days.
B. Because trees of same species may cause the spread of disease.
C. Because modern orchards and forests are more specialized.
D. Because trees planted crowdedly do not have enough room to develop their roots.
[单项选择]Why is the mixed planting of trees of the same species advocated in modern orchards and forests
A. Because mixed forests and orchards are the recognized procedures these days.
B. Because trees of same species may spread disease.
C. Because orchards and forests are modern.
D. Because trees planted crowdedly do not have enough room to develop their roots.
[单项选择]Why does the crocodile put her babies in her mouth
A. To keep them warm.
B. To protect them from harm.
C. To transport them to the water.
D. To clean them.
[单项选择]Why did the farmer put the pills in the tube
A. To make the cow take them.
B. To make himself feel strange.
C. To throw them away.