11. The author of the passage refers to a thick layer of dust that is deposited in a single event most likely in order to
Answer: E
Suggest a possible explanation for the inactivity of dunes found on Mars
The author refers to a thick layer of dust that is deposited in a single event to suggest a possible explanation for why dunes on Mars become inactive. This contrasts with the gradual processes observed on Earth and highlights the unique conditions that affect Martian dunes.
A) compare climatic conditions on Earth with those on Mars
This option is incorrect as the passage does not primarily focus on comparing climatic conditions between Earth and Mars. While it mentions climate, the emphasis is on how dust accumulation affects dune activity specifically on Mars rather than a comparative analysis of the two planets' climates.
B) compare active and inactive dunes
Although the passage discusses both active and inactive dunes, the reference to the thick layer of dust is not meant as a comparison between the two states. Instead, it serves to explain why Martian dunes become inactive, making this option not the main focus of the author's argument.
C) compare dust dunes with sand dunes
This option is also incorrect as the passage does not draw a direct comparison between dust dunes and sand dunes. The mention of dust relates specifically to the inactivity of sand dunes on Mars, rather than comparing their characteristics with dust dunes.
D) describe the effects of vegetation on dunes found on Earth
This choice is not accurate as the passage discusses vegetation only in the context of Earth, without elaborating on its effects on dunes. The primary focus is on Martian dunes and the specific conditions leading to their inactivity, rather than detailing the role of vegetation in Earth's dune dynamics.
E) suggest a possible explanation for the inactivity of dunes found on Mars
This option is correct because the author specifically refers to the occurrence of a thick layer of dust deposited in a single event to explain how dunes on Mars can become inactive. This distinct process is crucial in understanding the differences in dune activity between Earth and Mars.
Conclusion
The correct answer is E, as it directly addresses the author's intention to provide an explanation for the inactivity of dunes on Mars due to the particular conditions of dust accumulation. All other options fail to capture the main point of the passage, which centers on Martian dune inactivity rather than broader comparisons or unrelated factors.