The ocean bottom ― a region nearly 2.5 times greater than the total land area of the

            Earth ― is a vast frontier that even today is largely unexplored and uncharted, Until

            about a century ago, the deep-ocean floor was completely inaccessible, hidden beneath

 Line     waters averaging over 3,600 meters deep. Totally without light and subjected to intense

 (5)       pressures hundreds of times greater than at the Earth's surface, the deep-ocean bottom

            is a hostile environment to humans, in some ways as forbidding and remote as the void

            of outer space.

                 Although researchers have taken samples of deep-ocean rocks and sediments for

            over a century, the first detailed global investigation of the ocean bottom did not

 (10)      actually start until 1968, with the beginning of the National Science Foundation's Deep

            Sea Drilling Project (DSDP). Using techniques first developed for the offshore oil and

            gas industry, the DSDP's drill ship, the Glomar Challenger, was able to maintain a

            steady position on the ocean's surface and drill in very deep waters, extracting samples

            of sediments and rock from the ocean floor.

 (15)           The Glomar Challenger completed 96 voyages in a 15-year research program that

            ended in November 1983. During this time, the vessel logged 600,000 kilometers and

            took almost 20,000 core samples of seabed sediments and rocks at 624 drilling sites

            around the world. The Glomar Challenger's core sample have allowed geologists

            to reconstruct what the planet looked like hundreds of millions of years ago and to

 (20)      calculate what it will probably look like millions of years in the future. Today, largely

            on the strength of evidence gathered during the Glomar Challenger's voyages, nearly

            all earth scientists agree on the theories of plate tectonics and continental drift that

            explain many of the geological processes that shape the Earth.

                  The cores of sediment drilled by the Glomar Challenger have also yielded

 (25)      information critical to understanding the world's past climates. Deep-ocean sediments

            provide a climatic record stretching back hundreds of millions of years, because they

            are largely isolated from the mechanical erosion and the intense chemical and biological

            activity that rapidly destroy much land-based evidence of past climates. This record has

            already provided insights into the patterns and causes of past climatic change ―

            information that may be used to predict future climates.

 

            1. What is the main topic of the passage?

               (A) Marine life deep in the ocean

               (B) The Earth's climate millions of years ago

               (C) The first detailed study of the bottom of the ocean

               (D) Geologists' predictions for the future environment of the Earth

 

            2. The author refers to the ocean bottom as a "frontier" in line 2 because it

               (A) is not a popular area for scientific research

               (B) contains a wide variety of life forms

               (C) attracts courageous explorers

               (D) is an unknown territory

 

            3. The word "inaccessible" in line 3 is closest in meaning to

               (A) unrecognizable

               (B) unreachable

               (C) unusable

               (D) unsafe

 

            4. The author mentions outer space in line 7 because

               (A) the Earth's climate millions of years ago was similar to conditions in outer space

               (B) it is similar to the ocean floor in being alien to the human environment

               (C) rock formations in outer space are similar to those found on the ocean floor

               (D) techniques used by scientists to explore outer space were similar to those used in

                   ocean exploration

 

            5. Which of the following is true of the Glomar Challenger?

               (A) It is a type of submarine.

               (B) It is an ongoing project.

               (C) It has gone on over 100 voyages.

               (D) It made its first DSDP voyage in 1968.

 

            6. The word "extracting" in line 13 is closest in meaning to

               (A) breaking

               (B) locating

               (C) removing

               (D) analyzing

 

            7. The Deep Sea Drilling Project was signigicant because it was

               (A) an attempt to find new sources of oil and gas

               (B) the first extensive exploration of the ocean bottom

               (C) composed of geologists from all over the world

               (D) funded entirely by the gas and oil industry

 

            8. The word "strength" in line 21 is closest in meaning to

               (A) basis

               (B) purpose

               (C) discovery

               (D) endurance

 

            9. The word "they" in line 26 refers to

               (A) years

               (B) climates

               (C) sediments

               (D) cores

 

            10. Which of the following is NOT mentioned in the passage as being

                a result of the Deep Sea Drilling Project?

                (A) Geologists were able to determine the Earth's appearance hundreds

                  of millions of years ago.

                (B) Two geological theories became more widely accepted by scientists.

                (C) Information was revealed about the Earth's past climatic changes.

                (D) Geologists observed forms of marine life never before seen.