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 arc 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 (CO2 ) 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% water. Structural parts of plants, such as woody stems no longer actively growin
A. the functions of carbon dioxide and water
B. the role of water in a growing plant
C. the process of simple sugar formation
D. the synthesis of water with carbon dioxide
These days a green building means more than just the color of the paint. Green buildings can also refer to environmentally friendly house, factories, and offices.
Buildings account for 65 percent of total U. S. electricity use. But green buildings can reduce energy and water use. Also, the buildings are often located near public transportation such as buses and subways, so that people can drive their cars less. That could be good for the environment, because cars use lots of natural resources such as gasoline, and give off pollution. Green buildings are often built on previously developed land, so that the buildings don’t destroy forests or other wild habitats(栖息地).
Marry Dettling is project manager for a building that puts these ideas into action. The Solaire has been called the country’ s first green residential high-rise building. According to Dettling, "We’ve reduced our energy consumption by one-third and our water by ,50 percen
A. continue the discussion of total U. S. electricity use
B. shift the focus to the topic of the environment protection
C. include the discussion of public transportation
D. expand the topic of the reduction of energy and water use
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