A. Net Library is not a good way for the consumers.
B. There is no need for consumers to have a whole book.
C. E瑽rary is not a good library for the consumners.
D. It's reasonable to charge the consumers money for copying some pages.
Ⅲ. 阅读简答(10 min.)s certainly cannot run away, and they lack teeth and claws. But plants can defend themselves by using both physical and chemical means.
Some plants have their own ways to keep animals away. For example, the leaves of the holly plant have sharp spines (刺) that discourage grasseating animals. Holly leaves on lower branches have more spines than leaves on upper branches. This is because the lower leaves are easier for most animals to reach.eaves that are difficult for animals to eat. Some grasses may contain a sandy material; eating such grasses wears down the animal's teeth.
Many plants also have chemical defenses. Some plants produce chemicals that taste bitter or cause an unpleasant reaction. Some plants may fight against an attack by increasing the production of these chemicals. When a caterpillar (毛虫) bites a tobacco leaf, the leaf produces a chemical messenger. This messenger sends to the roots the information to produce more nicotine. The higher levels of nicotine discourage the caterpillar.
Many plants depend on both physical and chemical defenses. A certain plant in China, for instance, has prickly (多刺的) leaves, (毒液). A single experience with this kind of plant will teach an animal to stay away from it in the future. 1. Why does the Holly plant have more spines on the lower leaves? (No more than 13 words)___________________________
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