A single species that has evolved into several different forms that live in different ways has undergone "b. convergent evolution" since the multiple "divergent" species are seen to "converge" into a single species if you go back far enough in time.
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.
They are not afraid but they try and avoid getting wet because they cannot fly when wet
