An old man and his grandson were walking along a deserted beach at sunset. The little boy became concerned about all the starfish that had washed up on the beach. He bent down and, one by one, began to return them to the safety of the waves. "What do you think you are doing?" said the man gently to his grandson.

"I'm throwing these starfish back into the ocean, " said the little boy. "It's low tide now and all these starfish have been washed up onto shore. If I don't throw them back into ...