According to the fluid mosaic model, cell membranes are semi-fluid, where lipids and integral proteins are diffused randomly. In recent years, this model has been modified. In this regard, which of the following statements is incorrect?
A. Proteins can travel within the lipid bilayer
B. Proteins can remain continued within certain domains of membrane
C. Proteins can also undergo flip-flop movements in lipid bilayer
D. Mary proteins remain completely embedded within lipid bilayer

Hint: Plasma membrane is also called as biological membrane found In all cells of living organisms, where it is the membrane that separates the interior of the cell to the external environment, and it has various functions such as protection, and exchange of substances, etc.

Complete answer: The fluid mosaic model of the plasma membrane is the most important and acceptable model which was given by the scientist singer and Nicholson in the year 1972.
Where the plasma membrane is made up of different types of components such as phospholipids, proteins, and carbohydrates, etc.
Most of the percentage of cell membrane components is phospholipids arranged as players which restrict the entry of substances and also to separate the external environment to the interior of the cell.
When coming to an arrangement of phospholipid layer it is arranged in the form of a bilayer, where they consist of hydrophilic heads and hydrophobic tails, where both layers of hydrophilic heads are attached and appear as three layers with heads sandwiched between hydrophobic tails. So this phospholipid layer is amphiphilic.
Another important constituent of the plasma membrane is integrated proteins which are integrated with other competencies, and this is important to appear as a fluid mosaic.
Whereas this fluid mosaic model was later modified, where the quasi fluid nature of the lipids allow the proteins to flip-flop in the bilayer of the plasma membrane.
After proteins, another important component of the cell membrane is carbohydrates which are present on the external surface of the cells, and these carbohydrates are associated with other components to form glycolipids and glycoproteins, etc.
So the correct option is C.

Note: fluid mosaic model is the most accepted cell membrane model, which is composed of various components out of which phospholipid layer is a major one and all other like proteins and carbohydrates are arranged as they are embedded in it, this is the reason it got the name fluid mosaic model.