سوال ۲ کنکور ارشد ریاضی ۱۴۰۴
PART A: Vocabulary — Choose the word or phrase (1), (2), (3), or (4) that best completes each sentence.
The weakened ozone ................, which is vital to protecting life on Earth, is on track to be restored to full strength within decades.
پاسخ صحیح: گزینهٔ A — layer
This is a collocation / vocabulary item: only one choice forms a natural English phrase with ozone and fits the meaning of the sentence.
The fixed compound noun in English is the ozone layer — the region of the stratosphere that absorbs most of the Sun's ultraviolet radiation and is therefore "vital to protecting life on Earth." The sentence describes this region being weakened (thinned by ozone depletion) and now on track to be restored to full strength, which exactly matches the real-world recovery of the ozone layer.
Checking the distractors:
| Option | Meaning | Why it fails |
|---|---|---|
| 1) layer | a sheet/stratum of material | Correct — "ozone layer" is the standard collocation and fits the meaning |
| 2) level | an amount or height/degree | "ozone level" means a concentration; a level is not "vital to protecting life" as a physical shield, and you would not say a level is "restored to full strength" |
| 3) brim | the top edge of a cup / a hat's rim | unrelated to ozone; wrong meaning |
| 4) ingredient | a component of a mixture | ozone is a gas/shield, not an ingredient; does not collocate |
Hence the answer is (1) layer.
Exam trick: In sentence-completion vocabulary items, first look for a fixed collocation with the surrounding content words ("ozone ___"). The idiomatic partner is almost always the key, and the descriptive clause ("vital to protecting life on Earth") is there to confirm it.