Are you afraid to raise your hand in class, even when you know the answer If you are, most people would say that you’re shy.
If you feel shy, you’re not alone. Nine out of ten people are at least a little shy. But however shy you are, scientific evidence seems to show that it isn’t your fault. You may have been born that way.
How do psychologists measure shyness One way is by observation. They keep detailed records of people’s actions—like how often these people speak to others, or how long it takes someone to say hello to a stranger.
Another way to measure shyness is to ask people questions. The test only takes about 10 minutes. It asks questions like "Do you like going out a lot" and "Do you have many friends" People must answer either yes or no. These questions can predict how people actually behave in social situations. Suppose the test tells you that someone is shy. Chances are good that that person wi
A. Nobody will laugh at you for being shy.
B. Shyness is difficult to overcome.
C. Because many people don’t know how to behave in social situation.
D. Because most people are shy by nature.
Plant Gas
Scientists have been studying natural sources of methane for decades but hadn’t regarded plants as a producer, notes Frank Keppler, a geochemist at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. Now Keppler and his colleagues find that plants, from grasses to trees, may also be sources of the greenhouse gas. This is really surprising, because most scientists assumed that methane production requires an oxygen-free environment.
Previously, researchers had thought that it was impossible for plants to make significant mounts of the gas. They had assumed that microbes need to be in environments without oxygen to produce methane. Methane is a greenhouse gas, like carbon dioxide. Gases such as methane and carbon dioxide trap heat in Earth’s atmosphere and contribute to global warming.
In its experiments, Keppler’s team used sealed chambers that contained the same concentration of oxygen that Earth’s a
A. It was produced from plants.
B. It was not a greenhouse gas.
C. It was produced in oxygen-free environments.
D. It traps more heat than any other greenhouse gas.
| Perhaps the most familiar plant
movement belongs to one species of mimosa called the sensitive plant. Within
seconds, it can lower its leaves and make its tiny leaflets close up like
folding chairs. This movement is thought to be initiated by electrical impulses
remarkably similar to nerve signals in animals. But without the animals’
sophisticated motion machinery, the mimosa has had to be creative in devising a
way to move. For motion, the plant depends on tiny, bulb-shaped organs located at the base of each leaf stalk and leaflet. Called pulvini, these organs hold the plant parts in place. When the mimosa is stimulated—say, by a crawling insect or a sudden change in temperature—an electrical impulse sweeps through the plant. This causes potassium and then water to be shifted from certain cells in the pulvini to others, quickly turning one side of the o A. geographical distribution of plant and animal species B. location and purpose of the pulvini C. appearance of the mimosa D. process that causes movement in the mimosa [填空题]What price do the richer countries always raise
The prices they get from ______ are always rising. 我来回答: 提交
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