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A vaccine is a medical material that mimics the pathogen, but in a harmless way. When our body's immune fights it off, it remembers how to fight the real pathogen when it enters our body. So, it protects us from diseases.
Answer: Like fats, they are typically composed of fatty acid chains attached to a backbone of glycerol. Instead having three fatty acid tails, however, phospholipids generally have just two, and the third carbon of the glycerol backbone is occupied by a modified phosphate group.
