Final answer:
Homeoviscous adaptation is a biological phenomenon that allows organisms to maintain the fluidity and stability of their cell membranes in different environments.
Step-by-step explanation:
Homeoviscous adaptation is a biological phenomenon observed in organisms to maintain the fluidity and stability of their cell membranes in different environments. It is a mechanism that allows organisms to adjust the composition and properties of their cell membranes in response to changes in temperature and other environmental conditions. For example, in cold environments, organisms may increase the proportion of unsaturated fatty acids in their cell membranes to maintain fluidity and prevent freezing.