The fluid mosaic model of the plasma membrane was proposed by:

Correct answer: (b) Singer and Nicolson

Explanation

The fluid mosaic model of the plasma membrane was proposed by S. J. Singer and Garth Nicolson in 1972.

The membrane is a lipid bilayer in which proteins are embedded or attached, like a mosaic. It is fluid: the lipids and many proteins can move sideways within the layer. This explains how the membrane can change shape, fuse with other membranes, and let cells grow and divide.

• Watson and Crick gave the structure of DNA.
• Robert Hooke named the "cell" in 1665.
• J. D. Robertson proposed the earlier unit membrane model.