Answer:
Phospholipids form the basic structure of a cell membrane, called the lipid bilayer. Scattered in the lipid bilayer are cholesterol molecules, which help to keep the membrane fluid consistent. Membrane proteins are important for transporting substances across the cell membrane
Composting is a form of waste that uses organic materials to put into plants in order to help them grow and flourish. It saves energy, and it doesn't give off many gasses to help the Earth.
However, it is ineffective on the large scale and cannot be mass produced to help Earth instantly because of the large amounts of inorganic materials.
The most abundant protein is dead epidermal structures such as hair and melanin.
The cell membrane functions as a selective barrier. We call these kind of membranes as differentially permeable or semi permeable membrane. It can decide what substances can pass in and out. Therefore it can surround the cytoplasm (which is the inside of a cell) to separate the cell's content from the surroundings.