Cell membrane

It was hard for me to choose the right topic from section B. The fifth option was the one I found best. The goal is to explain the cell membrane structure and, mentioning examples, to discuss the mechanisms by which materials move into and out of animal cells.
The cell membrane, also called plasma membrane, is a very complex structure. Its task is to regulate a constant traffic of materials into and out of the cell. The main part of the cell membrane is a huge amount of phospholipid molecules, ordered into a bilayer. Each phospholipid has a hydrophilic, “water-loving” head and a couple of hydrophobic, “water-fearing” tails.