Which statement is true about the plasma membrane?
a. the proteins make up the matrix of the membrane.
b. the model can be likened to a sandwich where phospholipids are like the bread and proteins are like the filling.
c. the fluid nature of the membrane is regulated by flip-flopping of the phospholipids from one side of the membrane to the other.
d. proteins and phospholipids can move sideways within the plane of the membrane.

The correct answer is option D.

Explanation:

The plasma membrane is the outer membrane of the cell that surrounds the cytoplasm and other cell organelles found in it. The plasma membrane acts as a barrier between the outside of the cell and the inner side of the cell. This membrane has a lipid bilayer and has a hydrophilic head and hydrophobic tail.

Phospholipids and many membrane proteins are moves in lateral or transverse motion, movement of lipids and proteins called lateral diffusion.

Thus, the correct answer is option D.

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