Which statement best describes the difference between adaptation and acclimatization?

Which statement best describes the difference between adaptation and acclimatization?

• A. Acclimatization is a reversible, short-term adjustment to environmental change.
• B. Adaptation is a long-term, often genetic or irreversible change that improves function.
• C. Adaptation is reversible, short-term adjustment.
• D. Acclimatization is irreversible change.

Answer: (B)

Adaptation involves genetic changes in a population over many generations that improve how well the organism functions in a given environment. Because these traits are inherited, they persist across generations and aren’t something an individual can simply reverse during its lifetime. In contrast, acclimatization is a reversible adjustment that an individual makes within its own lifetime in response to environmental changes, and these changes can fade if conditions revert.

So the best way to describe the difference is that adaptation is a long-term, often genetic or irreversible change that improves function, while acclimatization is a reversible, within-individual adjustment to new conditions. For example, adaptation explains why certain populations evolve traits like metabolic efficiencies or coloration over many generations, whereas acclimatization explains how a single person might increase red blood cell production when moving to high altitude and then return to baseline if they stay low.