The first two decades of this century were dominated by the microbe hunters. These

            hunters had tracked down one after another of the microbes responsible for the most

            dreaded scourges of many centuries ; tuberculosis, cholera, diphtheria. But there remained

 Line     some terrible diseases for which no microbe could be incriminated : scurvy, pellagra,

  (5)      rickets, beriberi. Then it was discovered that these diseases were caused by the lack of

            vitamins, a trace substance in the diet. The diseases could be prevented or cured by

            consuming foods that contained the vitamins. And so in the decades of the 1920's and

            1930's, nutrition became a science and the vitamin hunters replaced the microbe hunters.

                In the 1940's and 1950's, biochemists strived to learn why each of the vitamins was

 (10)      essential for health. They discovered that key enzymes in metabolism depend on one or

            another of the vitamins as coenzymes to perform the chemistry that provides cells with

            energy for growth and function. Now, these enzymes hunters occupied center stage.

            You are aware that the enzyme hunters have been replaced by a new breed of hunters

            who are tracking genes ― the blueprints for each of the enzymes ― and are discovering

 (15)      the defective genes that cause inherited diseases ― diabetes, cystic fibrosis. These gene

            hunters, or genetic engineers, use recombinant DNA technology to identify and clone genes and introduce them into bacterial cells and plants to create factories for the massive of hormones and vaccines for medicine and for better crops for agriculture.                 Biotechnology has become a multibillion-dollar industry.

 (20)      In view of the inexorable progress in science, we can expect that the gene hunters

            will be replaced in the spotlight. When and by whom? Which kind of hunter will dominate

            the scene in the last decade of our waning century and in the early decades of the next ?

            I wonder whether the hunters who will occupy the spotlight will be neurobiologists

            who apply the techniques of the enzyme and gene hunters to the functions of the brain.

 (25)      What to call them? The head hunters. I will return to them later.

            24. What is the main topic of the passage?

              (A) The microbe hunters

              (B) The potential of genetic engineering

              (C) The progress of modern medical research 

              (D) The discovery of enzymes

            25. Which of the following can be cured by a change in diet?

              (A) Tuberculosis

              (B) Cholera

              (C) Cystic fibrosis

              (D) Pellagra

            26. How do vitamins influence health?

              (A) They are necessary for some enzymes to function.

              (B) They protect the body from microbes.

              (C) They keep food from spoiling.

              (D) They are broken down by cells to produce energy.

            27. In the third paragraph, the author compares cells that have been

                genetically altered by biotechnicians to

              (A) gardens

              (B) factories

              (C) hunters

              (D) spotlights

            28. The phrase“occupy the spotlight”in line 23 is closest in meaning to

              (A) receive the most attention

              (B) go the furthest

              (C) conquer territory

              (D) lighten the load

            29. The author implies that the most important medical research topic of the

                future will be

              (A) the functions of the brain

              (B) inherited diseases

              (C) the operation of vitamins

              (D) the structure of genes

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