Recently，scientists attending a meeting in Chicago presented new studies showing how food and its production affect global warming.They offered some suggestions for how to eat in a more environmentally friendly way.
For many years，scientists have warned us that our planet is getting warmer.If current trends continue，animals may start to die off and life could get very difficult for everyone.The temperature is rising because humans have been releasing massive amounts of greenhouse gases into the atmosphere，which surround the planet and keep heat from escaping.One of these gases is carbon dioxide.
Most carbon dioxide we produce comes from the process of making and eating food，the scientists reported in Chicago.The production of meat contributes to a lot of carbon dioxide.And much of meat’s contribution comes from beef，which is responsible for releasing even more greenhouse gases into the atmosphere.
The process of making a hamburger，for example，requires a lot of energy.A cow has to be fed and raised，and cow’s wastes are a major source of greenhouse gases.After the cow is killed，the meat has to be processed and shipped to a consumer，which takes fuel.And most of the cow won’t even be used for meat people eat.
By the time a hamburger finally lands on a dinner plate，it has taken a heavy toll on the environment.It is believed that the process of making a halfpound allbeef burger adds about 19 times the weight of hamburgers in carbon dioxide.
The message is clear：We can greatly reduce the production of greenhouse gases by eating less beef.Other kinds of meat like pork and chicken do less harm to the environment—at least in terms of the amount of greenhouse gases released.Nathan Pelletier，a scientist at Dalhousie University in Canada，reported that if everyone in industrial countries ate chicken instead of beef，we would cut the Earth’s greenhouse gases by more than half.
All kinds of meat，the scientists reported，are harder on the planet than vegetables.To grow and eat a pound of potatoes，for example，sends less than one quarter pound of carbon dioxide into the air.So shifting our diet to less meat and more vegetables may do the world some good.
The text mainly tells us ________.

A．what we eat can affect the whole planet

B．the way we live affects the environment

C．how we can save energy on the Earth

D．how we can produce environmentfriendly food

What is likely to happen if the climate is getting warmer according to the passage?

A．Sea level will continue to rise sharply.

B．Human beings won’t have enough food.

C．It would be very hard for man to survive.

D．All the animals and plants will disappear.

Why does the author mention the process of making a hamburger?

A．To show meat is usually part of a hamburger.

B．To illustrate that our food contributes to greenhouse gases.

C．To prove making a hamburger is a complex process.

D．To suggest a lot of energy is needed to make hamburgers.

The author believes one effective way to fight global warming is ________.

A．we should eat no pork and no chicken

B．we should eat more chicken than beef

C．we should eat not meat but vegetables

D．we should eat less meat and more vegetables

Which of the following statements would Nathan Pelletier agree to?

A．Eating pork and chicken is more environmentally friendly.

B．Meat consumption is the main cause of greenhouse gases.

C．People in industrial countries consume more beef than fish.

D．Eating more beef is a more efficient way to save more energy.