Answer:
The cell membrane is selectively permeable, which controls the movement of materials in and out of the cell by passive and active transport.
Explanation:
According to this question, animal cells are made up of the following contents: 90% water and 10% protein, carbohydrates, nucleic acid, lipids and other molecules. The cell regulates this internal composition in a stable way via a process called HOMEOSTASIS.
The animal cell is able to regulate or maintain a stable internal composition by the possession of a selective permeable membrane called CELL MEMBRANE. The cell membrane is semi-permeable in the sense that it allows the entry of some molecules into and out of the cell and blocks others.
Some molecules are allowed by the cell membrane without the need for energy input in a transport called PASSIVE TRANSPORT while some requires energy input in a transport called ACTIVE TRANSPORT.
