A rather surprisingly geographical feature of Antartica 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 Antartica. 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 reseach team was conducting an aerial survey of the area. Radio waves from the survey equipment penetrated the ice and reveal a body of water of undeterminate 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 Antartica 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 the 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 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.
31. The word “hidden” in paragraph 1 is closest in meaning to ____________.
A. undrinkable B. untouched C. unexploitable D. undiscovered
32. 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.
33. Which of the following is closest in meaning to “frigid” in paragraph 1?
A. extremely cold B. easily broken C. quite harsh D. lukewarm
34. All of the following are true about the 1970 survey of Antartica 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.
35. It can be inferred from the passage that the ice would not be flat if _____________________.
A. there were no lake underneath B. the lake weren’t so big
C. Antartica weren’t so cold D. radio waves weren’t used
36. The word “microbes” in paragraph 3 could best be replaced by which of the following?
A. pieces of dust B. tiny bubbles C. tiny organisms D. rays of light
37. 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
38. The word “downside” in paragraph 3 is closest in meaning to ___________.
A. bottom level B. negative aspect C. underside D. buried section
39. The last paragraph suggests that scientists should be aware of___________.
A. further discoveries on the surface of Antartica
B. problems with satellite-borne radar equipment
C. ways to study Lake Vostok without contaminating it.
D. the harsh climate of Antartica
40. The purpose of the passage is to____________.
A. explain how Lake Vostok was discovered
B. provide satellite data concerning Antartica.
C. discuss future plans for Lake Vostok
D. present an unexpected aspect of Antartica’s geography.
