Passage 2Questions 6 to 10 are based on the following passage.In the last 500 years, nothing about people-their clothes, ideas, or languages-has changed as much as what they eat.The original chocolate drink was made from the seeds of cocoa tree by South American Indians.The Spanish introduced it to the rest of the world during the 1500's.Although it was very expensive, it quickly became fashionable. In London,shops where chocolate drinks were served became important meeting places. Some still exist today.The potato is also from the New World.Around 1600, the Spanish brought it from Peru to Europe, where it soon was widely grown.The potato was the main food at Irish table.Thousands of Irish people starved when the crop failed during the"Potato Famine" (士豆饥荒) of 1845～1846, and thousands more were forced to move to America.There are many other foods that have traveled from South America to the old World. But some others went in the opposite direction. Brazil is now the world's largest grower of coffee,and coffee is an important crop in Colombia and other South American countries. But it is native to Ethiopia(埃塞俄比亚).it was first made into a drink by Arabs during the 1400's.(77) According to an Arabic story, coffee was discovered when a man named Kaldi noticed that his goats were attracted to the red fruits on a coffee bush. (78) He tried one and experienced the"wide-awake" feeling that one-third of the world's population now starts the day with.6. According to the passage, which of the following has changed the most in the last 500 years?