Detailed Instructions: In this task, you are given a multiple-choice question about healthcare. Answer the question based on your information and classify your answers into '1', '2', '3', and '4'.
Problem:Question: The degree of fluidity of the biological membranes depends on the percentage of:
Options: <1> Lipids with hill. <2> Glycolipids. <3> Sphingolipids <4> Free fatty acids. <5> Unsaturated fatty acids.
Solution:
5