阅读理解

     In England, everybody knows Jamie Oliver. He has his own TV programs. In these programs, he tells people how to cook healthy food. Everyone likes Jamie's programs because his food is easy to make.
     Jamie wants people to eat healthily. In some schools in England, the food at lunch time was't healthy. One day, Jamie went to a school to make a TV program about healthy diet. He cooked the food with lots of fruit and vegetables. At first the children didn't want to eat because they didn't like fruit or vegetables. But after they tasted the food, they started to enjoy it.
     Now the food for children in schools has become much healthier.

以下是某校学生制作并观察某细胞临时装片的相关图片，图甲是操作步骤，图乙是根据观察绘制的细胞模式图，请分析回答

（1）图甲中c图中滴在载玻片中央的液体是____．

（2）图乙中②代表____，图乙所示细胞与植物细胞的主要区别是没有____ ．

（3）观察时，为了使物像更清晰应调节图丙中____ ．

（4）口腔上皮属于组织，是细胞分裂和____ 的结果，植物体与人体相比没有的结构层次是____．

（2015•垫江县）将干燥的小麦种子放在酒精灯上燃烧，最后剩下的灰白色物质是（ ）