Describe three characteristics of cell membranes

Explanation:

The cell membrane, also called the plasma membrane, has the following characteristics:-

It is present as the outermost layer in animal cells and lies below the cell wall in plant cells.

The cell membrane surrounds the cytoplasm of living cells, physically separating the intracellular components from the extracellular environment.

The cell membrane is semi-permeable, ie, it allows some substances to pass through it and does not allow others.

It is thin, flexible and a living membrane, which consists of a lipid bilayer with embedded proteins/

The cell membrane has large content of proteins, typically around 50% of membrane volume. These proteins are important for cell because they are responsible for various biological activities.

the answer is d.) homologous; have mammary glands