题目

 No one can believe that the over 6 300-kilometer long Great Wall might disappear some day.Believe it or not,the Great Wall is being destroyed by people.Less than 20 percent of the Great Wall built in the Ming Dynasty is still perfect,but about 80 percent is in danger.The Great Wall can be called “great” mostly because of its amazing length.But we should realize that the length was made up of one brick at a time.If we do nothing to save the Great Wall,it will become a series of separate wasteland rather than a historic site. The Great Wall is actually a series of walls built and r下列不属于叶绿体基质成分的是（   ） A．可溶性蛋白质     B．核酸       C．光合色素        D．核糖体