The structure of the membrane, is the Phospholipid Bilayer. I hope this helps
The two substances are rock (molten and solid) and metal (solid + liquid).
Layers of the earth from the outside in:
1. crust. hard rock/dirt/ground. Shell
2. mantle. melted rock and stuff. Egg white
3. core. Outer core - liquid. Inner core- solid. Nickle and iron. Yolk
The inferior vena cava brings deoxygenated blood back into the heart from the lower body. For comparison, the part that directs deoxygenated blood from the upper body is the superior vena cava.