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Life on mars: Does it exist?

In 1976, two American spacecraft landed on Mars in order to search for signs of life. The tests that the Viking landers performed had negative results. However, scientists still have questions about our close neighbour in space. They want to investigate further into the possibility of life on Mars.

Scientists’ interest in the Red Planet is based on an assumption. They believe that 4. 5 billion years ago, Mars and Earth began their existence under similar conditions. During the first billion years, liquid water – in contrast to ice – was abundant on the surface of Mars. This is an indication that Mars was much warmer at that time. Mars also had a thicker atmosphere of carbon dioxide (CO2). Many scientists think it is possible that life began under these favourable conditions. After all, Earth had the same conditions during its first billion years, when life arose. At some point in time, Earth developed an atmosphere which is rich in oxygen and an ozone layer. Ozone (O3) is a form of oxygen. The ozone layer protects the Earth from harmful ultraviolet light from the sun. While life not only began on Earth, it also survived and became more complex. In contrast, Mars lost its thick atmosphere of carbon dioxide. Ultraviolet radiation intensified. The planet eventually grew colder and its water froze)…)

Scientist believe there are other areas on mars that are similar to specific places on Earth which support life. For example, an area in Antarctica, southern Victoria Land, which is not covered by ice, resembles an area on mars. In its dry valleys, the temperature in southern Victoria land averages below zero, yet biologists found simple life forms (microorganisms) in rocks and frozen lakes. Perhaps this is also true of places on Mars.

Scientists want another investigation of Mars. They want to search for fossils, the ancient remains of life. if life ever existed on mars, future missions may find records of it under sand or in the ice.

Even if future missions discover no evidence of past or present life on mars, the new missions may clarify our understanding of how life begins. Scientists will better understand the conditions that are necessary for the survival of life – on earth or in the universe. They will look for the answers to other intriguing questions. How is the Earth different from mars? How can we explain the development of life here on our planet and not on Mars, our close neighbor? Are we alone in the universe?

46. What is the main idea of the passage?

A. Two spacecraft looked for evidence of life on mars, but they were unsuccessful

B. Scientists are interested in the possibility that there is or wad life on Mars.

C. Mars is quite similar to Earth but there is no form of life on it.

D. Scientists are interested in how Mars is different from the Earth.

47. The phrase “ our close neighbour in space” refers to_______

A. the Viking spacecraft B. the Sun C. Mars D. people living on Mars

48. Which of the following statements is true?

A. Mars is much older than Earth

B. The Earth is much older than Mars

C. Mars and the Earth are the same age

D. Mars was much warmer than Earth during the first billion years

49. According to paragraph 2, what form does the water on Mars have today?

A. liquid B. solid C. gas D. we don’t know

50. What do CO2 and O3 in paragraph present?

A. chemical symbols B. abbreviations C. amount of gases D. the elements of the atmosphere

51. According to paragraph 4, what are fossils?

A. a source of fuel B. a part of natural resources

C. the ancient remains of life D. the ancient remains of Martians

52. What is the purpose of the dash (--) as used in the last paragraph?

A. to add extra information B. to give a definition

C. to give an explanation or example D. to connect two sentences

53. In the beginning, Earth and Mars were similar in that_________

A. liquid water was abundant on their surface B. their atmosphere was rich in oxygen

C. simple forms of life arose on both planets D. they both lost their thick atmosphere of carbon dioxide

54. Which of the following is true?

A. American spacecraft discovered life on Mars in 1976.

B. Scientists do not want to investigate life on Mars any more

C. Scientists believe there is liquid water on mars now

D. Scientist believe they may find ancient remains of life on mars under sand or ice.

55. According to the passage, in the future scientists want to look for_____

A. evidence of past and present life on Mars

B. the conditions necessary for the survival of life on Mars

C. the explanation for the development of life on earth but not on Mars

D. the answers to the environment problems