[填空题]A rat can learn and form new memories in its brain under the effect of

[填空题]A rat can learn and form new memories in its brain under the effect of

[单项选择]It can be inferred that a rat with its infralimbic cortices destroyed would respond which of the following ways to a tone previously conditioned to induce a fear response
Ⅰ. It would demonstrate fear if extinction had occurred the previous day.
Ⅱ. It would demonstrate fear if extinction had occurred earlier than the previous day.
Ⅲ. It would demonstrate fear even if extinction had never occurred at all.
A. Ⅰ only
B. Ⅱ only
C. Ⅰ and Ⅱ only
D. Ⅰ and Ⅲ only
E. Ⅰ, Ⅱ, and Ⅲ

[单项选择]In terms of its tone and its form, the passage can best be characterized as
A. a critical analysis
B. a speculative study
C. a dispassionate presentation
D. an indignant denial
E. a dogmatic explanation

[填空题]Zinc can help reproduce many new brain cells.

[单项选择]

Man has a big brain. He can think, learn and speak. Scientists used to think that men are different- from animals because they can think and learn. They know now that animals--dogs, rats and birds--can learn. So scientists are beginning to understand that men are different from animals because they can speak. Animals cannot speak. They make noises when they are afraid, or hungry, or unhappy. Apes are our nearest cousins. They can understand some things more quickly than human beings, and one or two have learned a few words. But they are still different from us. They cannot join words and make sentences. They cannot think like us because they have no language. They can never think about the past or the future. Language is a wonderful thing. Man has been able to develop civilization because he has language. Every child can speak his own language very well when he is four or five-but no animal learns to speak. How do children learn Scientists do not really know. What happens when we
A. teaching apes a few words
B. expressing ourselves well
C. developing our civilization
D. understanding the animals