CAT 2025 Slot 2 · VARC · Question 23

CAT 2025 Slot 2 previous year question on Odd One Out, with the answer and a step-by-step solution.

Odd One OutVerbal AbilityType in the answer (TITA)Medium

Five jumbled sentences (labelled 1, 2, 3, 4, and 5), related to a topic, are given below. Four of them can be put together to form a coherent paragraph. Identify the odd sentence out and key in the number of that sentence as your answer.

  1. Pfas are a class of about 15,000 compounds most frequently used to make products water-, stain- and grease-resistant.
  2. New research suggests exposure to some common perfluoroalkyl and polyfluoroalkyl substances (Pfas) cause changes to gene activity and that these changes are linked to health problems including multiple cancers, neurological disorders and autoimmune disease.
  3. These Pfas compounds are dubbed "forever chemicals" because they do not naturally break down in the environment.
  4. The research may also point toward other diseases potentially caused by Pfas that have not yet been identified.
  5. The findings are a major step toward determining the mechanism by which the chemicals cause disease and could help doctors identify, detect and treat health problems for those exposed to Pfas before the issues advance.
Answer & solution

Answer: 3

Identify the paragraph's subject precisely. Sentences 2, 4 and 5 are all about one thing: new research linking Pfas exposure to disease, what else it may reveal, and what it enables doctors to do. That is a research-and-disease paragraph.

Sentence 2 opens it – it introduces Pfas in full and states the finding. Sentence 4 extends the finding to diseases not yet identified. Sentence 5 states the significance, a step toward the mechanism and toward earlier detection and treatment.

The contest is between 1 and 3 for the fourth slot. Sentence 1 defines what Pfas are and what they are used for, which supports a paragraph introducing these chemicals to a reader.

Sentence 3 is about environmental persistence – why they are called 'forever chemicals' because they do not break down in the environment. Persistence in the environment is a different concern from gene activity and disease, and nothing else in the set picks it up. Sentence 3 is the odd one out.

Shortcut: with two candidate outliers, ask which one the remaining sentences could use. A definition can serve almost any paragraph about a substance; a fact about environmental persistence serves only a paragraph about pollution. The more specialised fact is the one that does not belong.

Hence, the answer is 3.

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