Value based questions.
Cells of poikilothermic (cold-blooded) animals usually have a higher proportion of unsaturated fatty acids than homeothermic (warm.blooded) animals. Can you account for this?

Body temperature of poikilothermic animals become lower in cold environments. Lipids rich in unsaturated fatty acids (which have low melting points) generally remain liquid at temperatures lower (usually 5C or lower) than those rich in saturated fatty acids. It is necessary if the lipid is to maintain its function, such as constituent of membrane.