Which of the following statements is logically equivalent to the statement 'Some plants are carnivorous organisms'?

ANo carnivorous organisms are plants

BSome plants are non-carnivorous organisms

CNo plants are non-carnivorous organisms

DSome plants are not non-carnivorous organisms ✓ Correct

Correct answer: (D) Some plants are not non-carnivorous organisms

Explanation

The obverse of Some plants are carnivorous organisms is Some plants are not non-carnivorous organisms.

Obversion changes the quality and replaces the predicate with its complement.

An I proposition obverts into an O proposition with the complemented predicate.

Some S are P thus becomes Some S are not non-P, preserving truth exactly.

Obversion is a valid immediate inference for every categorical form.

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