Under which conditions would a cell membrane be MOST likely to be in a liquid, crystalline state, in which an individual phospholipid can rotate around its axis or move laterally through the plane of the bilayer?

Answer: Normal body temperature

Explanation:

The lipid bilayer shows free lateral movement of its components, this makes the membrane to be fluid in nature.

Certain conditions increases or decreases the fluidity of membrane

1. Temperature: at about the normal body temperature 37 degrees celsius the membrane is fluidity increses and at lower temperature the membrane becomes more viscous.

2. Cholesterol content of the membrane alters the fluidity. When cholesterol concentration increases the membrane becomes less fluid on the outer surface but more fluid in the hydrophobic core.

3. The nature of fatty acids also affects the fluidity of the membrane, the more unsaturated cis fatty acids increase the fluidity. While trans fatty acids decreases fluidity.