Membrane lipids are capable of many different types of movement. Which of these does not occur spontaneously in biological membranes?

Membrane lipids are capable of many different types of movement. Which of these does not occur spontaneously in biological membranes?

1. Witching between lipid bilayers
2. Lateral movement
3. Rotation
4. Flexing of hydrocarbon chains

Answer: The correct answer is Witching between lipid bilayers