Think about what you usually have for a meal: Is it a hamburger? What about vegetables? Would it surprise you to learn that what you eat can affect the whole planet? It can--in a big way. Scientists attending the American Association for the Advancement of Science meeting in Chicago presented new studies showing how food and its production affect the globe and its warming climate. It is generally believed that global warming is caused by the large amounts of greenhouse gases released into the atmosphere. One of these greenhouse gases is carbon dioxide. What does this have to do with food? A big part of the carbon dioxide comes from the process of making and eating food, the scientists reported in Chicago. The production of meat contributes to a lot of that carbon dioxide. The process of making a hamburger, for example, requires a lot of energy. A cow has to be fed and raised on farmland, and cow manure is a major source of methane --an especially powerful greenhouse gas. By the time a hamburger is finally served on a dinner plate, it has done great harm to the environment. The message from the research is clear: We can greatly reduce the production of greenhouse gases by eating less meat. 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 or other greenhouse gases into the air. So shifting our diet to less meat and more vegetables ,as it turns out, may do the world some good. According to the passage , the writer seemingly intends to   _  .
appeal to us to protect the environment by eating less meat food. persuade us to develop a good eating habit to keep healthy advise us to make less hamburgers in order to save energy. encourage us to grow more vegetables to reduce greenhouse gases.