Worms,Your Unlikely Allies etc

• 来源期刊: 中学科技
• 年，卷（期）: 2012,（2）
• 所属期刊栏目: 科普英语
• 页码范围: 32-33
• 页数: 2页
• 语种: 中文

摘要

Back in the Stone Age,humans had to put up with all sorts of creepy crawlies.Parasites - organisms that live on or in another organism - lingered inside our bodies,living off of our blood.Because internal parasites go mostly unnoticed,they were able to keep living with humans.People can survive a long time with tiny parasitic worms in their intestines.