C

    Jackson was driving back home along a road one evening. He just lost his job. It was winter and it was very cold, just like his feelings.

    An old lady with her car was standing on one side of the road. The lady looked very worried. She needed help. No one stopped to help her. Jackson stopped in front of her and got out of his car. Even when he put a smile on his face, the old lady still looked worried. Was he going to hurt her? He didn't look safe, and he looked poor and hungry.

    Jackson knew how she felt. He said." I'm here to help you, madam. Why don't you wait in my car? By the way, my name is Jackson."

    The lady thought for a while and then went into his car. There was something wrong with her car. Jackson went under her car to repair it. After a long time, he finished it. He got dirty and his hands hurt. Then the lady told him that her name was Annie. She asked Jackson how much she should pay for his help.

    Jackson never thought about getting money. This was not a job to him. This was helping someone in need. He told her that if she really wanted to pay him back, the next time she saw someone who needed help, she should give that person help.

请分析并回答下列问题：

在一片水稻田的生态系统中，昆虫以水稻为食，青蛙以昆虫为食。三者的相互关系可以用下图表示，图中各长方形的长度分别表示上述三种生物的数量，长方形越长，表示该生物的数量越多。请根据图回答有关问题：

（1）写出图中各字母所表示的生物：A____ 、B____ 、C____ 。
（2）该生态系统中，生产者是____ ，消费者是____ 。
（3）如果大量捕食青蛙，该生态系统中数量会明显增加的生物是____ ，明显减少的生物是____ 。