Phospholipids will form a bilayer in water because they contain hydrophobic (Water fearing.. in this cause water "hating") tails and hydrophilic heads (water loving). So they form a bilayer to remove the tails from water likewise, this satisfies the hydrophilic heads because they are still exposed to water.
D. lactobacillus is the right answer
The reactive CARBONYL GROUP, contributes to the ability of aldehydes and ketones to be involved in energy reactions. Aldehydes and ketones undergo different types of reactions that lead to various products. One example of these reactions are nucloephilic reactions which lead to the production of alcohols, alkenes, diols, imine, etc.