A few organisms can tolerate and thrive only within a narrow range of environmental temperatures. Such temperature sensitive organisms are known by which of the following terms?

Introduction / Context:
Ecology studies how organisms interact with their environment, including physical factors such as temperature. Different species show different tolerances to temperature variation. Some can survive over a broad range, while others can live only within a narrow band of temperatures. This question asks you to recognize the correct term for organisms that thrive in a narrow temperature range.

Given Data / Assumptions:

• The environmental factor under consideration is temperature.
• The organisms described can tolerate and thrive only in a narrow temperature range.
• Options include osmotic, eurythermal, stenothermal and hydrothermal organisms.
• We assume standard ecological terminology.

Concept / Approach:
The terms eurythermal and stenothermal describe the breadth of temperature tolerance. Eurythermal organisms can tolerate wide variations in temperature and survive in environments with large seasonal or daily temperature changes. Stenothermal organisms, in contrast, can tolerate only a narrow range of temperatures and are often restricted to stable environments. Osmotic refers to osmotic pressure, not temperature tolerance. Hydrothermal is a descriptive term related to hot water environments, not a standard tolerance category used in basic ecology texts. Therefore, the correct term for organisms described in the question is stenothermal.

Step-by-Step Solution:
Step 1: Focus on the key phrase, narrow range of temperatures, which signals limited tolerance to temperature change.Step 2: Recall that stenothermal organisms are defined as those that can live only within a narrow temperature range.Step 3: Recall that eurythermal organisms have broad temperature tolerance and would not match the narrow range description.Step 4: Examine option C, stenothermal organisms that tolerate only a narrow range of temperatures, and see that it matches the definition exactly.Step 5: Reject option A because osmotic tolerance concerns salt concentration or osmotic pressure, not temperature.Step 6: Reject option B because eurythermal describes the opposite condition, that is, wide tolerance.Step 7: Reject option D because hydrothermal is not a standard term for tolerance range and simply refers to hot water environments.Step 8: Conclude that stenothermal is the correct term.

Verification / Alternative check:
Ecology chapters in biology textbooks often present tolerance curves showing how population performance varies with a factor such as temperature. They describe eurythermal species, which have wide tolerance limits and broad curves, and stenothermal species, which have narrow curves and are restricted to specific temperature ranges. Polar fishes and some deep sea organisms are commonly cited examples of stenothermal species. This terminology confirms that organisms restricted to narrow temperature ranges are called stenothermal.

Why Other Options Are Wrong:
Option A is wrong because osmotic tolerance relates to solute concentration in water and is typically described with terms like osmoregulation and osmoregulators, not temperature range. Option B is wrong because eurythermal organisms can live in a wide range of temperatures, contrary to the narrow range described. Option D is wrong because hydrothermal simply describes hot water conditions such as near hydrothermal vents but does not define a general tolerance category for narrow temperature range in standard ecological terminology.

Common Pitfalls:
Students sometimes confuse eurythermal and stenothermal because both contain the root thermal. A useful memory aid is to link eury with the idea of broad or wide, as in Europe spanning many climates, and steno with narrow. Another pitfall is being distracted by words like hydrothermal, which sound technical but do not appear as standard tolerance categories in basic ecology. By focusing on the definitions and remembering that stenothermal equals narrow temperature tolerance, you can reliably answer such questions.

Final Answer:
Stenothermal organisms that tolerate only a narrow range of temperatures.