First-class students (7)

I believe the answer is:

infants

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'first-class students' is the definition.
The definition and answer can be both people as well as being plural nouns.
Maybe you can see a link between them that I can't see?

This is the entire clue.

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(Other definitions for infants that I've seen before include "Little ones" , "Small babies" , "Very small humans" , "Very young children" , "Young babies" .)

I've seen this clue in The Telegraph, The Irish News and The Globe and Mail.

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