According to the author, what may the difficult psychological stage of high school students be called

A．It was about American women instead of the American revolution.
B．The professor made a good speech.
C．The professor talked about a trip and he was challenged.
D．The professor was challenged by a student by his lack of knowledge of female historical character.

A．To show some men depend on a particular food.
B．To show the diet of some people is still primitive.
C．To show different people eat different foods.
D．To show the adaptability of man in terms of his diet.