托福阅读真题+题目+答案：Plant-Animal Adaptations

托福阅读真题+题目+答案：Plant-Animal Adaptations

Plants and animals often evolve by adapting to each other; for example, plants evolve defenses against herbivory (animals feeding on plants). Spiny cacti, poisonous hemlock, thorny rosebushes, and prickly thisties are all particularly unpleasant defense is used by plants in the milkweed family, which get their common name because their leaves and stems, when cut, ooze a white sap. However, only in appearance is the spa milky--it is sticky an thick, and, in many species, it has chemical irritants that make it even more noxious to touch or taste. Nevertheless, many insects are able to feed on milkweed. Milkweed beetles overcome this defense in an innovative way: by biting repeatedly into the midrib (central vein) of the milkweed leaf. The sap leaks out through the bite holes before it reaches the tips of the leaves, where the beetle can then feed without its mouthparts becoming too full and feeding reduce the plant’s ability to photosythesize (convert sunlight into chemical energy for food).

1.According to paragraph 1, spiny cacti, poisonous hemlock, thorny rosebushes, and prickly thistles are examples of which of the following?

A.Plants that have evolved by adapting to one another

B.Plants that have evolved defenses against animals that feed on them

C.Plants that have evolved unusual strategies for photosynthesizing

D.Plants that use chemical irritants to prevent animals from touching or tasting them

2.According to paragraph 1, a milkweed beetle biting into the midrib of the milkweed leaf harms the plant because it

A.damages the structures in the milkweed plant that produce sap

B.makes it harder for the milkweed plant to produce energy for food

C.reduces the milkweed plant’s ability to take in essential nutrients from the soil

D.removes much-needed moisture from the milkweed plant

While roots, stems, and leaves are often defended, fruits and flowers have evolved to attract animals. Most ripe fruit is red or black, such as raspberries and blackberries. Is this because these colors have evolved to attract frugivores (fruit eaters) that will disperse the seeds? Birds, one of the main frugivores, have four types of retinal cones (cells responsible for seeing color) that give them excellent color vision. Foraging birds do prefer red and black fruits--but not because they are attracted to the color itself. Instead, red and black fruits contrast well with the typical green background of foliage, and it is this contrast that attracts birds.

3.The word “disperse” in the passage is closest in meaning to

A.eat

B.recognize

C.spreed

D.collect

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