We think of winter as cold and flu season, but the chilly temperatures have powerful biological upsides too. Here are some ways cold weather helps your body.

21. ________.

Colder temperatures can help you think more clearly. Studies have found that people perform some cognitive tasks better when the temperature is cooler. Research has also shown that people are less inclined to tackle complex tasks in summer than in winter. The brain requires glucose (葡萄糖) to function, but the body uses more of it in warmer temperatures to keep the body cool.That leaves less available fuel for reasoning and recall tasks.

22.________ .

We know accumulating too much ordinary fat can endanger our health. But adults also have small amounts of beneficial “brown” fat that can help burn more calories--and cold temperatures can activate this brown fat. One study showed that participants who lowered their body temperatures simply by placing one foot in cold water did increase their brown fat cells.

23. ________.

If spring and summer make you sneeze, winter might be your new favorite season. Pollen (花粉) counts are virtually nonexistent in cold weather. Indoor allergies, however, can be worse during the winter. To ease indoor allergies, use a dehumidifier(减湿器)to maintain the humidity at home below 50 percent.

24. ________.

Your body’s core temperature drops when you’re trying to sleep. This process can take up to two hours in summer, but it’s much faster in winter. Plus, with darker mornings, you naturally sleep later.

25.________ .

Yes, you might get more colds during the winter. However, studies have shown that the immune system can be activated by colder temperatures, which enhances our ability to fight infections. That said, the flu virus thrives in cold, dry air, and time spent indoors increases your chance of infection. To reduce risk, get your annual flu shot, wash your hands frequently, and go outside.

A. Eases allergies

B. Kills flu viruses

C. Fights infections

D. Uses less glucose

E. Boosts your brain

F. Activates healthy fat

G. Encourages better sleep