1. (D) The loneliness of human beings
2. (A) The heron feeding on the snake in the pond
3. (D) The rabbits are part of George and Lennie's dream of one day having a farm of their own
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I think the one that learn the least is : The narrator's aunt. She kept making unreasonable accusation throughout the story. One of it was that she believed that the burglar has been coming to her house every night for the last 40 years. i might say that the one that learn the most would be the narrator himself.
Hope this helps