19. The dietitian's argument works this way:

 

	P1: Nutrients are most effective when provided by natural foods rather than through supplements
	P2: Fat in one's diet is generally unhealthy.
	P3: To convert beta carotene into vitamin A, the body requires that some fat be consumed with beta carotene.
	________________________________________
	C: Eating raw carrots alone is not an effective means of getting vitamin A.

The statement is a premise.

 

A paraphrase of (A): It is a premise to support consuming some fat, but not eliminating fat altogether. (A) is correct.

(B) states "least often", but the passage makes no mention of others who recommend other dietary practices.

(C) states "hypothesis", but the statement is presented as a fact.

(D) states "attacked", but the Dietitian states that it "is true".

(E) states "bad", but the author never makes such a judgment.

 

20. The author's conclusion is the first four words of the fourth sentence -- many environmentalists' worry ("This worry") is unfounded, and (C) is the correct choice.

The author does not take an extra step and then claim that any action should be taken on the basis of this information. Choices (A) and (E) provide guesses as to what the author might be leading up to.

(B) and (D) are premises.

 

21. The discrepancy:

	X	YET	Y
	More than half of those who ate seafood at the restaurant had not come in contact with the bacteria		Officials confident that contaminated seafood from restaurant caused several people to come down with illness

 

(A) states most people, which means more than half of all people, but the discrepancy is concerned with those who at ate seafood at the specific restaurant on a specific date.

(B) provides a conditional statement:

	Ill from bacteria g Served by a waiter who later became ill
	Served by a waiter who later became ill g Ill from bacteria

Although this provides more coincidental information, it does not explain why more than half of those who ate seafood did not even come into contact with the bacteria. The illness the waiter contracted and those served is not necessarily the same one, and, "subsequently" does not necessarily mean soon after -- it could be years. Also, it's possible that the waiter is the only server at the restaurant, and thus served all those who ate seafood on that particular day.

(C) does nothing to solve the discrepancy. The passage states that several people came down with an illness, not an allergic reaction. If the passage stated symptoms, then perhaps the allergies rather than the bacteria has caused the symptoms.

(D) provides a reason why the health officials might believe that the seafood at that particular restaurant had contaminated seafood, but does nothing to resolve the discrepancy.

(E) provides two conditional statements:

	Ate particular seafood dish g Contracted illness
	Contracted illness g Ate particular seafood dish

(E) guarantees that if you ate a specific dish, then you definitely got sick. If you didn't get sick, then you didn't eat the dish. Thus, it's possible that more than half of those who ate seafood at the restaurant did not have that particular dish, and thus did not come into contact with the bacteria. Also, all those who contracted the illness (i.e., every single case of the illness in the entire world) ate the dish at that restaurant.