CAT 2020 Slot 3 — VARC Question 24
The four sentences (labelled 1, 2, 3, 4) below, when properly sequenced would yield a coherent paragraph. Decide on the proper sequencing of the order of the sentences and key in the sequence of the four numbers as your answer:
1. Complex computational elements of the CNS are organized according to a “nested” hierarchic criterion; the organization is not permanent and can change dynamically from moment to moment as they carry out a computational task.
2. Echolocation in bats exemplifies adaptation produced by natural selection; a function not produced by natural selection for its current use is exaptation --feathers might have originally arisen in the context of selection for insulation.
3. From a structural standpoint, consistent with exaptation, the living organism is organized as a complex of “Russian Matryoshka Dolls” -- smaller structures are contained within larger ones in multiple layers.
4. The exaptation concept, and the Russian-doll organization concept of living beings deduced from studies on evolution of the various apparatuses in mammals, can be applied for the most complex human organ: the central nervous system (CNS).
Answer & solution
Answer: 2431
Easy
Find the sentence that defines the two governing concepts (these are what the rest apply), then track how each concept is taken forward. Watch the structural-to-specific drift, ending at the most specialised subject.
Opener (2). Sentence 2 introduces and defines the key terms with examples — “Echolocation in bats exemplifies adaptation… a function not produced by natural selection for its current use is exaptation.” It sets up the vocabulary the others reuse, so it opens.
Then 4. Sentence 4 takes the two ideas — “The exaptation concept, and the Russian-doll organization concept… can be applied for the most complex human organ: the central nervous system (CNS).” It bridges the general concepts to the CNS and names “Russian-doll organization,” setting up 3.
Then 3. Sentence 3 elaborates the structural picture — “consistent with exaptation, the living organism is organized as a complex of ‘Russian Matryoshka Dolls’ — smaller structures contained within larger ones in multiple layers.” It explains the nested image that 1 then applies.
Closer (1). Sentence 1 lands on the CNS specifically — its “complex computational elements… are organized according to a ‘nested’ hierarchic criterion,” mirroring the layered Russian-doll structure of 3. As the most specialised statement, it ends the paragraph: 2–4–3–1.
Note on alternatives. The official key is 2431 and that is the intended answer. The order 2341 is also defensible: 3’s nested-structure description could lead straight into 1’s nested CNS, with 4 introducing the doll concept before 3. Either way, 2 opens and 1 closes; the 3/4 ordering is the only genuine doubt.
The coherent order (per the official key) is 2431.