托福阅读真题+题目+答案：Roots The Hidden Tree

托福阅读真题+题目+答案：Roots The Hidden Tree

A common view of tree roots is that they plunge deep into the ground, producing almost a mirror image of the canopy-the uppermost part of the tree consisting of branches and leaves. In reality, the roots form a wide but shallow base. Most trees fail to root deeply because it is physically difficult and unnecessary. The two main functions of roots are to take up water and minerals and to hold the tree up. In normal situations. water is most abundant near e soil surface(from rain). This is also where the bulk of dead matter accumulates and decomposes, releasing minerals.
1.The word “abundant” in the passage is closest in meaning to

A.necessary

B.plentiful

C.full of nutrients

D.obtainable

2.It can be inferred from paragraph 1 that roots do not grow deep into the ground in part because

A.they must form a root system that is as wide as the width of the canopy

B.trees are most stable when their root system is shallow but wide

C.the nutrients they need can be found near the surface of the soil

D.they are prevented from growing too deep by decomposed matter near the surface

Roots also store food for later use, and they play an important role in determining the trees size. Roots normally account for 20 30 percent of a trees mass. If the trunk is ignored(40-60 percent o the total mass), however, the canopy and the roots have roughly the same mass, which helps put into perspective the relative value of the roots and the leaves to each other. Too few roots, and the canopy suffers from lack of water. Too few leaves, and the roots get insufficient food. The roots control the canopy partly through water supply but also by the production of hormones.
3.Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.

A.The trunk is of relatively little value to the tree in comparison to the canopy and roots

B.The canopy and the roots are about the same mass, which helps explain their relative value

C.The roots and leaves together are more valuable to the tree than the trunk

D.The value of the trunk is relative to the mass of the roots and leaves

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