Select the option that can be used as a one-word substitute for the given group of words. One who eats the flesh of his own species

Correct — D. A cannibal is one that eats the flesh of its own kind, and "of his own species" is exactly the restriction the word carries.

The other three options describe a diet in general terms, or describe no diet at all, and none of them contains the idea of eating one's own kind.

That restriction is the whole of the definition, so cannibal is the substitute that reproduces it.

Why the others are wrong

• (a)
  Vegan — A vegan eats no animal products at all, which is the far end of the scale from the cue. The word describes what is refused rather than what is eaten.
• (b)
  Non-vegetarian — Non-vegetarian covers anyone who eats meat of any sort. It carries no restriction to one's own species, and that restriction is what the definition is built on.
• (c)
  Mammal — Mammal is a taxonomic class, defined by hair, warm blood and milk-feeding. It says nothing about diet, so it cannot substitute for a phrase about eating.

One-word substitution rewards you for finding the load-bearing phrase in the definition and matching that phrase alone.

Here the load-bearing phrase is of his own species. Strip it out and the definition reads "one who eats flesh", which more than one option could answer. Keep it in and a single word survives.

Note also that cannibal is not restricted to human beings: it is used of any animal that eats members of its own kind, which is why the wording says species and not people.

Key facts

• Cannibal: an animal or a person that eats the flesh of its own species.
• Vegan: a person who avoids all animal products, including milk and eggs.
• Mammal names a class of animals and carries no information about diet.

Common traps

• Answering only the words eats the flesh and stopping there, which lands on Non-vegetarian.
• Reading species as a signal that a scientific term is wanted, and reaching for Mammal.

No directly related past PYQ was found.