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TEXT H
First read the following questions.
84. Pharmacologists and biologists are interested in sponges because _____.
A. they are primitive
B. of their digestive system
C. of the chemicals they produce
D. they are neither plant nor animal
正确答案是
Now read Text H quickly and select your answers.
Sponges are just barely animals, such as a borderline case that until the 19th century they were called zoophytes, the animal-plants. They are among the most primitive forms of multi-cellular animal life. But they have been around a long time and must be doing something right. More than 5,000 species inhabit this planet, living in fresh water and throughout the sea down to depths of more than 25,000 feet.
Often strikingly beautiful, sponges offer the added virtue of usefulness. Even with synthetic sponges widely available, a market for natural sponges persists. They hold more water without dripping, are easier to clean, and last longer, even under heavy use. And now, after centuries in the bathtub, sponges are finding their way into the laboratories of pharmacologists and cell biologists. As do so many marine invertebrates that have limited defenses in the usual sense (they are capable of neither fight nor flight), sponges produce some extremely powerful chemical compounds, toxic and otherwise, that hold great promise as future drugs for the treatment of human disorders, including cancer.
TEXT I