C. A wall of stones and mortar
This would act as a model describing the cell membrane.
Explanation;
A cell membrane is made up of a phospholipid bilayer with embedded proteins.
A cell membrane hold the different components of the cell together and to protect it from the environment outside the cell. It acts as a boundary between the inside environment and the outside environment of a cell.
It regulates the materials that enters and exits the cell; through selective movement of substances in and out of the cell.
“The test of any theory is whether or not it provides answers to basic questions. Some well-meaning but misguided people think evolution is a reasonable theory to explain man’s questions about the universe.”Where did the space for the universe come from? Witch can be experimented to answer.
It's the first one where it resist change in pH solutions by neutralizing :)