1. What does the passage mainly discuss?
(A) The effects of vitamins on the human body
(B) The history of food preferences from the nineteenth century to the present
(C) The stages of development of clinical nutrition as a field of study
(D) Nutritional practices of the nineteenth century
2. It can be inferred from the passage that which of the following discoveries was made during the first era in the history of nutrition?
(A) Protein was recognized as an essential component of diet.
(B) Vitamins were synthesized from foods.
(C) Effective techniques of weight loss were determined.
(D) Certain foods were found to be harmful to good health.
3. The word "tempting" in line 12 is closest in meaning to