题目

阅读理解 When people reunite with their loved ones, it's usually all extremely happy moment. But what is their most common response to seeing them again? It may seem strange，but most of the time they break down in tears. Now a group of psychologists from Yale University say they have found the reason why, and that crying tears of joy may well be the body's way of keeping emotional balance. “They seem to take place when people are overtaken by strong positive emotions, and people who do this seem to recover better from those strong emotions,” Oriana Aragon, the lead researcher said. A下列动物可以根据形态结构分为一类的是 [     ]A．虾、家兔、蚯蚓B．老鼠、马、猿猴C．鲫鱼、带鱼、牛 D．蝗虫、虎、蟾蜍