When you’re all comfortable and warm, watching the snowflakes pile up outside, you might wonder, what about the poor animals? No fire. No cocoa. No blankets.   
Well, it’s really people who aren’t designed to live in cold climates.    Geese have built-in down comforters. Bears have fur coats. Robins just fly south. But look at people. No fur. No feathers. No fair! And not everyone can jet off to Florida when it snows.
   Mainly, our big brains. Still, it’s taken us a long time to figure out how to cope with cold weather, and along the way we’ve borrowed a few tricks from the animals, too.
When you put on a jacket, you feel warm. Why? Because your jacket traps the heat your body produces. Your body uses the food you eat as fuel to stay warm.    Active muscles burn more fuel and produce more heat. That’s why you shiver when you’re cold. By shivering, your body is doing its best to get your muscles moving and warm you up.
  Even in the coldest weather, your brain needs lots of warm blood. That’s one reason why your feet and hands get cold --- your body is sending heat to your brain. If you put on a hat, you will find that your feet and hands get warmer.

A．How do they stand it?

B．It can no longer trap a layer of warm air.

C．If you run or jump around, you feel even warmer.

D．So what do people have to help beat the cold?

E. Animals have lots of cool ways to survive the winter.
F. That’s because water carries heat away from your skin.
G. The most important part of your body to keep warm is your brain.