【单选题】This type of learning, however, is called conditioning. The animal simply learns that when it performs a particular behavior, it gets a reward, usually a fish. Many animals, including rats, birds, and...
【简答题】People like to look in the mirror often when they have a young and beautiful face. However, when one grows old, nobody wants to see their wrinkled old face in the mirror any more. So, many old people ...