Option 1: Protein

Proteins are essential components of the cell, but they do not make up the cell wall in animal cells. Proteins have various functions in the cell, including structural support, enzymatic activity, and transport of molecules.

Option 2: Carbohydrate

Carbohydrates are important biomolecules, but they also do not make up the cell wall in animal cells. Carbohydrates have roles in energy storage and cell signaling, but not in providing structural support.

Option 3: Lipid bilayer

The correct answer is option 3. Animal cell walls are primarily composed of a lipid bilayer, known as the cell membrane. The cell membrane consists of phospholipids, which have a hydrophilic (water-loving) head and a hydrophobic (water-repelling) tail. The arrangement of phospholipids forms a barrier that separates the inner contents of the cell from the external environment.

Option 4: Cellulose

Cellulose is a component of cell walls in plant cells, not animal cells. Plant cell walls are primarily made up of cellulose, which provides rigidity and support to the plant. Animal cells do not have a cellulose-based cell wall.

In conclusion, animal cell walls