Which of the following statements are logically equivalent?

1.Some plants are non-fungi

2.Some plants are not fungi

3.Some fungi are plants

4.Some non-fungi are not non-plants

A2, 3 & 4 only

B2 & 3 only

C1, 3 & 4 only

D1, 2 & 4 only ✓ Correct

Correct answer: (D) 1, 2 & 4 only

Explanation

Statements 1, 2 and 4 all express the same particular negative content.

Statement 2 is Some plants are not fungi, the base O proposition.

Statement 1 is its obverse, Some plants are non-fungi, which is logically equal.

Statement 4 is its contrapositive, Some non-fungi are not non-plants, valid for O.

Statement 3, Some fungi are plants, is a different I claim and not equivalent.

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