A rather surprising geographical feature of Antarctica is that a huge freshwater lake, one of the world’s largest and deepest, lies hidden there under four kilometers of ice. Now known as Lake Vostok, this huge body of water is located under the ice block that comprises Antarctica. The lake is able to exist in its unfrozen state beneath this block of ice because its waters are warmed by geothermal heat from the earth’s core. The thick glacier above Lake Vostok actually insulates it from the frigid temperatures on the surface.

The lake was first discovered in the 1970s while a research team was conducting an aerial survey of the area. Radio waves from the survey equipment penetrated the ice and revealed a body of water of indeterminate size. It was not until much more recently that data collected by satellite made scientists aware of the tremendous size of the lake; the satellite-borne radar detected an extremely flat region where the ice remains level because it is floating on the water of the lake.

The discovery of such a huge freshwater lake trapped under Antarctica is of interest to the scientific community because of the potential that the lake contains ancient microbes that have survived for thousands   upon thousands of years, unaffected by factors such as nuclear fallout and elevated ultraviolet light that have affected organisms in more exposed areas. The downside of the discovery, however, lies in the difficulty of conducting research on the lake in such a harsh climate and in the problems associated with obtaining uncontaminated samples from the lake without actually exposing the lake to contamination. Scientists are looking for possible ways to accomplish this.

1. What is true of Lake Vostok?

A. It is completely frozen.                                      B. It is a saltwater lake.

C. It is beneath a thick slab of ice.                          D. It is heated by the sun.

2. Which of the following is closest in meaning to "frigid" in paragraph 1?

         A. rarely recorded          B. extremely cold             C. never changing             D. quite harsh

3. All of the following are true about the 1970 survey of Antarctica EXCEPT that it                            .

A. was conducted by air                                          B. made use of radio waves

C. could not determine the lake’s exact size           D. was controlled by a satellite

4. It can be inferred from the passage that the ice would not be flat if                       .

A. there were no lake underneath                           B. the lake were not so big

C. Antarctica were not so cold                               D. radio waves were not used

5. The word “microbes” in paragraph 3 could best be replaced by which of the following?

A. Tiny bubbles                B. Pieces of dust           C. Tiny organisms             D. Rays of light

6. Lake Vostok is potentially important to scientists because it ___________.

A. can be studied using radio waves                       B. may contain uncontaminated microbes

C. may have elevated levels of ultraviolet light     D. has already been contaminated

7. The last paragraph suggests that scientists should be aware of

         A. further discoveries on the surface of Antarctica

         B. problems with satellite-borne radar equipment

         C. ways to study Lake Vostok without contaminating it

         D. the harsh climate of Antarctica

8. The purpose of the passage is to                            .

         A. explain how Lake Vostok was discovered        B. provide satellite data concerning Antarctica

            C. discuss future plans for Lake Vostok   D. present an unexpected aspect of Antarctica’s geography