By components do you mean organs? If so...
1. Brain - gives demands ands orders to all of the body to function properly
2. Heart - pumps blood, and keeps the organism receiving the blood alive
3. Skin - protects the tissue from UV Rays that may be harmful
Answer: They are extremely Optimistic.
Cereal companies are blamed for putting too much sugar into their products, which causes obesity. This is bad for them, as it would stop people from bying their products. So they would have an interest in study showing that this is not the case: the study would be a self-interest study (the correct answer) and therefore not be reliable