Which pair of the following statements is contradictory, i.e. exactly one must…
2026
Which pair of the following statements is contradictory, i.e. exactly one must be true and the other must be false?
A. All pitcher-plants are carnivores.
B. No pitcher-plants are carnivores.
C. Some pitcher-plants are carnivores.
D. Some pitcher-plants are not carnivores.
Choose the correct answer from the options given below.
- A.
A and D only
- B.
C and D only
- C.
A and B only
- D.
B and D only
Attempted by 52 students.
Show answer & explanation
Correct answer: A
Correct answer: A and D only
Two categorical statements are contradictory when exactly one of them must be true and the other must be false. They cannot both be true and cannot both be false.
A: All pitcher-plants are carnivores. This becomes false if even one pitcher-plant is not a carnivore.
D: Some pitcher-plants are not carnivores. This becomes true exactly in that case.
A and D are contradictories: if A is true, D is false; if D is true, A is false.
A and B are only contraries: they cannot both be true, but they can both be false if some, but not all, pitcher-plants are carnivores.
Hence, only A and D satisfy the required relationship.