According to Gause's Competitive Exclusion Principle:

The correct answer is Option (3) → Two closely related species competing for the same resources cannot co-exist indefinitely and the competitively inferior one will be eliminated eventually.

Option (1) Two closely related species competing for the same resources can co-exist indefinitely and the competitively superior one will be eliminated eventually. — Incorrect. Both parts are reversed. The two species cannot live together for ever, and it is the weaker (inferior) species that is pushed out, not the stronger one.

Option (2) Two closely related species competing for the different resources cannot co-exist indefinitely and the competitively inferior one will be eliminated eventually. — Incorrect. Species that use different resources do not compete at all, so neither is pushed out.

Option (3) Two closely related species competing for the same resources cannot co-exist indefinitely and the competitively inferior one will be eliminated eventually. — Correct. All three parts of the principle are present: closely related, same resources, inferior one eliminated.

Option (4) Two closely related species competing for the different resources can co-exist indefinitely and the competitively superior one will be eliminated eventually. — Incorrect. It contradicts itself. If the two species can live together for ever, neither one is eliminated. And competition never removes the superior species.

Note: A similar question was also asked in CUET (UG) 2026 on 24-05-2026 (Slot 1), and in CUET (UG) 2025 on 30-05-2025 (Slot 1) and on 23-05-2025 (Slot 2).

NCERT Extract:
Population Interactions – “… Gause’s ‘Competitive Exclusion Principle’ states that two closely related species competing for the same resources cannot co-exist indefinitely and the competitively inferior one will be eliminated eventually. This may be true if resources are limiting, but not otherwise. More recent studies do not support such gross generalisations about competition.”