You absorb vitamin d from sunlight shining on your skin.
Vitamin d can help the absorption of calcium, which is capable for strengthening your bones and teeth.
Therefore if u r lacking of vitamin d, your bones and teeth may be soft, and especially among children, you may get ricket, where the legs are bent outwards.
The vegetable oil is made up of chains of long fatty acids. These long chains of fatty acids are non-polar in nature, i.e, they do not interact through ionic forces rather by covalent forces. The phospholipids are also long chain fatty acids with an ionic head. The mixing of the vial of phospholipid in vegatable oil will lead to the formation of a micelle where the lipophilic ends of the phospholipid will be on the outside and the lipophobic end will be towards the centre of the micelle.
A cell wall. Animal cells do not have a cell wall have plants have a cell wall.