| Most growing plants contain much more
water than all other materials combined. C. R. Barnes has suggested that it is
as proper to term the plant a water structure as to call a house composed mainly
of brick a brick building. Certain it is that all essential processes of plant
growth and development occur in water. The mineral elements from the soil that
are usable by the plant must be dissolved in the soil solution before they can
be taken into the root. They are carried to all parts of the growing plant and
are built into essential plant materials while in a dissolved state. The carbon
dioxide from the air may enter the leaf as a gas but is dissolved in water in
the leaf before it is combined with a part of the water to form simple
sugars—the base material from which the plant body is mainly built. Actively
growing plant parts are generally 75 to 90 perce A. (A) forming sugars B. (B) sustaining woody stems C. (C) keeping green D. (D) producing carbon dioxide [单项选择]Most growing plants contain much more water than all other materials combined. C.R. Dames has suggested that it is as proper to term the plant a water structure as to call a house composed mainly of bricks as a brick building. It is certain that all the essential processes of plant growth and development occur in water. The mineral elements from the soil that are usable by the plant must be dissolved in the soil solution before they can be taken into the root. They are carded to all parts of the growing plant and are built into essential plant materials while in a dissolved state. The carbon dioxide (CO2) from the air may enter the leaf as a gas but is dissolved in the leaf before it is combined with a part of the water to form simple sugars — the base material from which the plant body is mainly built. Actively growing plant parts are generally 75 to 90 percent water. Structural parts of plants, such as woody stems no longer actively growing, may have much less water than g
A. forming sugars B. sustaining actively growing parts as well as woody stems C. absorbing mineral elements D. taking in carbon dioxide from the air [单项选择]Americans use more water than any other people in the world. If we continue to use water at the rate we do now, we will soon not have enough to meet our needs. In 1980, 40 billion gallons were used each day in the United States. In 1990, 700 billion gallons were used. The average Americans uses almost 90 gallons of water a day for personal use. And much move water is needed to make the things American people like to have. For example, it takes thousands of gallons of water to make one pound of beef for the dinner table. It takes more than 100,000 gallons of water to make a car. If we include these uses of water, the average American uses about 2000 gallons of water a day.
Americans used ______ gallons of water each day in 1980. A. 40 billion B. 90 billion C. 700 billion D. 200 billion 我来回答: 提交
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