[A] in the late 19th century in the United States the dividing line between adolescence and adulthood no longer existed
[B] no one can marry without the permission of his parents until the age of twenty-one
[C] one is considered to have reached adulthood when he has a drivers license
[D] one is not free from the restrictions of child labor laws until he can join the army
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Text 3
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 (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 percent water. Structural parts of plants, such as woody stems no longer actively growing, may have much less water than growing tissues.
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