In the following passage, some of the words / sentences have been left out,…
2024
In the following passage, some of the words / sentences have been left out, each of which is indicated by a letter. Find the suitable word / sentence from the options given against each letter and fill up the blanks with appropriate words / sentences to make the paragraph meaningful.
The layer of ozone helps _____ 1 _____ the harmful ultraviolet rays away from entering the Earth’s atmosphere. Ozone layer depletion over the years has _____ 2 _____ in ozone hole formation through which harmful radiations can now enter the atmosphere. Ozone layer depletion has many _____ 3 _____ effects including cancer risks. These wavelengths can harm plants and animals and also cause skin cancer, sunburn, and cataracts in humans. The problem is very _____ 4 _____ indeed and has rightly generated global concern. These concerns led to the _____ 5 _____ of the Montreal Protocol in the year 1987. This protocol bans the production of ozone-depleting chemicals like CFCs and halons. Ozone depletion refers to a steady _____ 6 _____ in the total amount of ozone present in the Earth’s atmosphere or the ozone layer. It can also be described as a much larger decrease in stratospheric ozone around the polar regions of the Earth. The second phenomenon is termed as the ozone hole. In addition to these stratospheric events, there are also springtime polar tropospheric ozone depletion events. _____ 7 _____ . These compounds enter the stratosphere after being emitted at the surface where these compounds release halogen atoms by a process called photo dissociation. _____ 8 _____ . The main cause of ozone layer depletion is the indiscriminate use of CFCs, which are chlorine-based substances. These are widely used in several manufacturing plants, refrigerants and aerosols. _____ 9 _____ . Just one atom of chlorine can destroy around 100, 000 molecules of ozone. Wind blows the CFCs up into the stratosphere. Ozone molecules are already unstable. The chlorine atoms in the CFCs react with the ozone molecules, which break down resulting in the formation of an oxygen molecule and a single free-floating oxygen atom. _____ 10 _____ . However, chlorine in other places such as swimming pools does not pose any danger.
Find the appropriate word in case 7
(question no 6 to 15 are linked together)
- A.
It should be noted that such substances should not be entertained in day-to-day human life at all
so that there is no consequent health issue.
- B.
Such substances will result in various diseases for human beings if they are not controlled properly.
- C.
Man-made chemicals like solvents, propellants, halocarbon refrigerants, and foam-blowing agents (chlorofluorocarbon (CFCs), HCFCs, halons), also called ozone-depleting substances (ODS) are the major causes of the problem.
- D.
There are many substances which do not cause any problem but they are treated as harmful substances still.
Attempted by 3 students.
Show answer & explanation
Correct answer: C
Concept
A sentence-insertion cloze item like this is solved by tracking REFERENCE and TONE across the blank, not by which option merely 'sounds scientific'. When the sentence AFTER a blank uses a demonstrative phrase (here, "These compounds"), the blank itself must supply the concrete noun phrase that the demonstrative points back to — and it must keep the passage's declarative, cause-and-effect tone rather than shifting to advice or a contradicting claim.
Application
Map the two anchor sentences around blank 7:
Before: "In addition to these stratospheric events, there are also springtime polar tropospheric ozone depletion events." — introduces another ozone-depletion phenomenon but names no chemical.
After: "These compounds enter the stratosphere after being emitted at the surface where these compounds release halogen atoms..." — this sentence's "These compounds" needs an antecedent: a noun phrase naming specific chemicals must appear in the blank.
Only the option that lists concrete ozone-depleting chemicals can satisfy that need. The sentence "Man-made chemicals like solvents, propellants, halocarbon refrigerants, and foam-blowing agents (CFCs, HCFCs, halons), also called ozone-depleting substances (ODS), are the major causes of the problem." does exactly this — it supplies the antecedent "these compounds" then refers to, and it keeps the passage's factual, cause-and-effect register.
Contrast
Why each of the others breaks the chain:
"It should be noted that such substances should not be entertained..." — "such substances" is itself an unresolved demonstrative; it never names a chemical, and its advisory tone (what people "should" do) breaks from the passage's declarative explanation of cause and effect.
"Such substances will result in various diseases..." — again leaves "such substances" unnamed, and it duplicates the health-risk point the passage already makes later rather than introducing the chemicals "these compounds" needs to refer to.
"There are many substances which do not cause any problem but they are treated as harmful substances still." — this contradicts the passage's own repeated claim that these substances truly are harmful, and it still names no specific chemical.
Result: only the sentence naming CFCs, HCFCs, and halons as man-made ozone-depleting substances both matches the passage's tone and supplies the antecedent that "These compounds" requires next, making it the correct fill for blank 7.