Fact 1: Lipids may consist of fatty acids alone, or they may contain other molecules as well.

Fact 2: All biological membranes contain lipids as the major constituent.

Given the two facts above, answer the question "What is the major thing that biological membranes consist of?" with the following options: 
- chemicals
 - glucose
 - lipids
 - Energy
 - complex
 - oxygen
 - matter
 - an ion


 

   lipids      