Plants are adapted to the climate they live in for the most part. Trees in rainforests have broad leaves, shaped to encourage the heavy rain to run off the leaves. The large leaves encourage transpiration so the plants don’t overheat. In very dry climates plants may develop an ability to store water, such as the cactus, which also has its leaves reduced into tiny spines which reduce transpiration to almost nothing so its precious water is conserved. At the first sign of drought, plants close their leaf pores to prevent wilting and slowing down growth so that they need less water. Coniferous plants also have small spiky leaves so that they don’t lose too much water during the frozen winters. Grasses roll their leaves into tubes to protect their leaf pores from the drying effect of the wind. Tropical air plants have moisture sensitive plugs attached to their leaf pores which are pulled down over the pores, sealing them to hold in moisture, by the contraction of the stal
A. Animals yawn for a number of reasons.
B. Yawning results only from fatigue of boredom.
C. Human yawns are the same as those of other animals.
D. Only social animals yawn.
Plants are adapted to the climate they live in for the most part. Trees in rainforests have broad leaves, shaped to encourage the heavy rain to run off the leaves. The large leaves encourage transpiration so the plants don’t overheat. In very dry climates plants may develop an ability to store water, such as the cactus, which also has its leaves reduced into tiny spines which reduce transpiration to almost nothing so its precious water is conserved. At the first sign of drought, plants close their leaf pores to prevent wilting and slowing down growth so that they need less water. Coniferous plants also have small spiky leaves so that they don’t lose too much water during the frozen winters. Grasses roll their leaves into tubes to protect their leaf pores from the drying effect of the wind. Tropical air plants have moisture sensitive plugs attached to their leaf pores which are pulled down over the pores, sealing them to hold in moisture, by the contraction of the stal
A. Different animals’ yawn.
B. Human’s yawn.
C. Fish’s yawn.
D. Social animals’ yawn.
Plants in Desert
Only special plants can survive the terrible climate of a desert, for these are regions when the annual range of the soil temperature can be over 75℃. Furthermore, during the summer there are few clouds in the sky to protect plans from the sun’ s ray. Another problem is the fact that there are frequently strong winds that drive small, sharp particles of sand into the plants,earing and damaging them. The most difficult probiem for all forms of plant life, however, is the fact that the entire annual rainfall occurs during a few days or weeks in spring.
Grasses and flowers in desert survive from one year to the next by existing through the long, hot, dry season in the form of seeds. These seeds remain inactive unless the fight amount of’rain falls. If no rain falls, or if insufficient rain falls, they wait until the next year, or even still the next. Another factor that helps these plants to survive is the fact that their life cycl
A. Right
B. Wrong
C. Not mentioned
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