What is the function of the cell membrane

A cell membrane protects a cell from it's surroundings. The cell membrane controls the movement of substances from the outside and inside of cells and organelles.

The cell membrane, also known as the plasma membrane, is the outer covering of animal cells which sits inside the cell wall of plant cells. It is semi-permeable so it allows certain materials to go in and out of the cell. Substances that can pass easily in and out of the cells include oxygen, carbon dioxide, and water. So basically, it is separates the cytoplasm from the outside environment, allowing only certain molecules to enter and exit the cell and also controls the amount of the substances that can go in and out.

satellites are frequently used to make observations of the orbit on earth

a scenario where a cell may be needed to perform a form of endocytosis is when transporting large molecules. a scenario where a cell may be needed to perform a form of exocytosis is when releasing the large molecule from the cell.