Comprehension:
Read the following passage carefully and answer the questions that follow
There can be no greater example of a mankind’s creative genius than for him to create new abodes of life throughout the solar system. Today, with an increasing population of more than six billion people and the fear of possible disaster, the need for an alternate home for mankind has become urgent. Mars is the only planet in our solar system, besides Earth – that has all the ingredients necessary to support life. Though the average surface temperature on Mars is frigid and it is a desolate lifeless planet, Mars once had an atmosphere thick and warm enough to allow for the flow of liquid on its surface.
If it is ever done, transforming a dry, desert-like Mars into a lush environment that can support the flora and fauna of the Earth, will be a mammoth task requiring decades or maybe centuries! Two methods have been proposed to make this a reality. One is placing large orbital mirrors that will reflect sunlight and heat onto the polar caps of Mars, which would melt the ice there. Gradually, the rise in temperature would release the greenhouse gases and heat the planet.
Another option would be to set-up solar-powered, greenhouse gas producing factories. Imitating the process of photosynthesis, the atmosphere of Mars would be oxygenated to the extent that people would survive on Mars with only a breathing apparatus.
While we may reach Mars this century, it would take several millennia for transforming it into a planet wherein plants and animals can flourish.
Choose the most appropriate option to complete the following:
The solar-powered greenhouse factories on Mars would replicate the process of photosynthesis to_____________ .
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → oxygenate the atmosphere
The passage says that by imitating photosynthesis, "the atmosphere of Mars would be oxygenated" (supplied with oxygen), so that people could survive there with only a breathing apparatus.
Why the Other Options are Incorrect?
Option 1: absorb carbon dioxide and reduce pollution — Incorrect. Not mentioned: the passage does not speak of pollution on Mars; the factories are meant to add oxygen.
Option 2: make it lush green — Incorrect. Too broad: a lush planet is the far-off goal of the whole plan, which the passage says would take millennia; it is not what the factories themselves would do.
Option 4: create a breathing apparatus for humans — Incorrect. Contradicted: the factories would change the atmosphere; people would still need their own breathing apparatus.