18. During the subsequent lull in hunting, the seal population made a good, although temporary, recovery.
A. stop             B. stillness
C. quietness        D. pause

19. A mutation happens to suit a new environment, and the “odd” creature survives because it is better fitted.
A. calcium          B. remnant
C. alteration       D. eradication

20. This is an unexplored area in vitamin research and the only known advantages of vitamin E are confined to specialized medical cases.
A. assessed in        B. restricted to
C. contributed to     D. expected on

III. Directions: Scan Passage 1 and find the words which have roughly the meanings given below. Write the word you choose in the corresponding space on your ANSWER SHEET.(10 points, 1 point for each)
    Note: The numbers in the brackets refer to the numbers of paragraphs in the passage.

21. conditions and surroundings that affect people’s lives (1)
22. passing on of physical or mental characteristics from parents to children (2)
23. have an effect on each other (2)
24. way in which something works (3)
25. power of learning, understanding and reasoning (4)
26. controlling or handling something with skill (4)
27. characteristics and qualities of a person (5)
28. deciding the value or amount of something (6)
29. explaining something which is not easily understandable (6)
30. make something difficult to see clearly (6)

Passage 1
1. We inherit genes, not traits. When we say that a boy got his brown eyes from his father, we really mean that he got the genes for brown eyes from his father. Every gene must develop in an environment, and the environment influences how that gene will develop. In the case of fruit flies, the vestigial(退化的)-wing characteristic will develop if the flies are raised at room temperature. If the flies are reared at about 92oF（33oC）, however, the wings will be almost normal.

2. In the final analysis, the question, “Which is more important, heredity or environment?” has no meaning. There can be no “heredity versus environment” situation: both factors, heredity and environment, must interact for an organism to develop.

3. Still, we can get some idea of the relative contributions of heredity and environment to certain traits. To do this, we must determine the genetic mechanism for a particular trait. We must also determine how much effect the environment can have on the trait. Neither of these determinations is easy, but for a few traits they have both been made.

4. In the case of Down’s syndrome, for example, we know that the presence of an extra number 21 chromosome sets limits on the development of the intelligence and largely determines certain other abnormal characteristics of the victim. Unfortunately, no amount of environmental manipulation can cause the victim’s intelligence to exceed a certain “subnormal” level. Thus we can say that in the development of the phenotype of a person with Down’s syndrome, heredity makes a relatively great contribution— by imposing severe limits.