Select the organisms that can tolerate wide range of temperatures:

The correct answer is Option (1) → Eurythermals

Option (1) Eurythermals — Correct. Eury- means wide, so eurythermal organisms live across a wide range of temperatures. Stenothermal organisms (option 2) are limited to a narrow range.

Option (2) Stenothermals — Incorrect. Stenothermal organisms can live only within a narrow range of temperature; most organisms are of this kind.

Option (3) Conformers — Incorrect. Conformers cannot keep their body temperature constant; it changes with the surroundings. The term is about regulating, not about how wide a range can be tolerated.

Option (4) Osmoregulators — Incorrect. Osmoregulators keep the water and salt balance of the body constant; the term concerns salinity, not temperature.

Note 1: A similar question was also asked in CUET (UG) 2023 on 05-06-2023 (Slot 2).

Note 2: This question is from the topic “Major Abiotic Factors” in Chapter 13, Organisms and Populations, of the pre-rationalised NCERT book. This portion is not in the present NCERT book, where the chapter is now Chapter 11, Organisms and Populations. The extract below is from the pre-rationalised edition.

NCERT Extract (Pre-rationalised edition, Chapter 13, Organisms and Populations):
Major Abiotic Factors – “… A few organisms can tolerate and thrive in a wide range of temperatures (they are called eurythermal ), but, a vast majority of them are restricted to a narrow range of temperatures (such organisms are called stenothermal ). The levels of thermal tolerance of different species determine to a large extent their geographical distribution.”