The answer is egg! I really hope this helps you out!
Answer:
All cells share four common components: (1) a plasma membrane, an outer covering that separates the cell’s interior from its surrounding environment; (2) cytoplasm, consisting of a jelly-like region within the cell in which other cellular components are found; (3) DNA, the genetic material of the cell; and (4) ribosomes, particles that synthesize proteins. However, prokaryotes differ from eukaryotic cells in several ways.
If you look at a picture of a cell membrane (http://apbiomaedahs.weebly.com/uploads/1/8/4/0/18405139/593679327_orig.jpg?510)
you'll see that there are 2 layers (bi- means 2) of the yellow things (the round heads are hydrophilic and the tails are hydrophobic and face each other), hence the name lipid bilayer