Answer:
1.capsule
2.membrane composed mostly of lipopolysaccharide
3.membrane composed mostly of phospholipids
4.peptidoglycan
Explanation:
The cell wall of gram-negative bacteria is located outside the cell membrane and is composed of a single layer of peptidoglycan, followed by a second membrane composed of phospholipids (often called outer membrane) and finally a lipopolysaccharide layer, these three elements constitute the gram-negative envelope. Also, some bacteria produce a viscous secretion that spreads in the surrounding environment, forming a slime layer known as a capsule.