Question

All plant cells are able to take up water. Even dead ones do to a certain degree. Absorption of water by dead cell walls makes wood swell(肿胀). In common land plants, the living cells of roots take up most of the water. Land plants without roots do exist, however. Those greenish-yellow lichens(苔藓)you see on tree trunks and on rocks in the high mountains have no roots. Half a billion years ago, when water plant started to invade the land, the first primitive land plants did not have roots; they were marsh (沼泽) plants.

Even among the flowering plants, one finds rootless forms. These flowering plants are the so-called higher plants because they evolved more recently and are thus considered higher on the evolutionary scale. In the Peruvian desert, there grows one of these rootless higher plants, a bromeliad. It is a relative of the pineapple. Even if this plant had roots, they would be of no use, because where the plant grows, it never rains. The plant gets its water exclusively from the dew it collects at night, when its leaves cool off. Such rootless plants, of course, can be moved with ease, but they will only grow when they are placed out in the open. If they are placed too near a house, the radiation from the heat of the house prevents the leaves from cooling and so prevents dew from forming, and the plant dies. In the southern United States and in Puerto Rico, one sees bromeliads growing high above the streets on the insulation of electric wires. These plants get their water from rain, and the only soil they ever come in contact with is the dust that may blow on their leaves.

Wood swells because of _______.

A. the dead cell walls          B. tiny drops of water entering the dead cell

C. the growth of the cell       D. the death of the cell

From the passage we know that the evolutionary scale is arranged according to ______.

A. evolutionary cycles                  B. heights and depths

C. time                                D. kinds

The bromeliad is a plant that _______.

A. has useless roots             B. is a pineapple

C. can grow anywhere           D. takes up water through its leaves

Which of the following is NOT true?

Water plants existed before land plants.

Only living plant cells take up water.

The greenish-yellow lichens are uncommon land plants.

The living cells of roots absorb more water than the rest of the plant.

The most suitable title for this passage is ______.

A. water intake by cells  B. rootless plantsC. plant in the desert   D. higher plants

Answer 1

【小题1】B

【小题2】C

【小题3】D

【小题4】B

【小题5】A

解析:

【小题1】

【小题2】

【小题3】

【小题4】

【小题5】