They need to cope with changing seasons and be able to withstand cold winters and hot summers
A mixture
If the elements or compounds aren't chemically bonded then they are known as a mixture :)
Lipids that make up our cell membranes are phospholipids, and they're awfully similar to soap. They consist of glycerol<span> attached to a phosphate group and to two </span>fatty acids<span>, or carboxylic acids.</span>