Assertion (A): The Fluid Mosaic Model of the plasma membrane was given by Singer and Nicholson.
Reason (R): Cell membrane is selectively permeable in nature.

Correct Answer:

Both assertion and reason are correct, but the reason is not the correct explanation of assertion.

 Extra information:

The plasma membrane is called a selectively permeable membrane because it permits only certain molecules to move in and out of the cell. All molecules are not free to diffuse into the cell.