Jack went to a barber’s shop and had his hair cut, but when he came out, he was not  h____  with the result. When his friend Bob saw him, he  l____  and said, “What happened to your hair, Jack?”
   Jack said, “I tried a new barber’s shop today, because I wasn’t quite satisfied with the  o____  one, but this one seems even w____ .”
   Bob agreed. “Yes. I think you are right, Jack. Now I’ll tell you  w____  to do when you go into a barber’s shop  n____  time. Look at the barber’s hair, find out whose hair  l____  worst, and then go straight to him.”
   “Why shall I go to him?” Jack asked, “But that would be foolish.”
   “Oh, no, it wouldn’t.” said Bob. “Who cut that man’s  h____ ? Just think it over. He couldn’t cut it   h____ , could he? One of the  o____  barbers cut it. So you know he can’t be the worst barber.”

 人体有四种基本组织，它们分别是上皮组织、结缔组织、神经组织和____ 组织，其中具有保护和分泌功能的是____ 组织。