6.No senator spoke at the convention unless he or she was a Democrat. No Democrat both spoke at the convention and was a senator.

  Which one of the following conclusions can be correctly drawn from the statements above?

  (A) No one but senators spoke at the convention.

  (B) No Democrat spoke at the convention.

  (C) Only Democrats spoke at the convention.

  (D) No senator spoke at the convention.

  (E) Some Democrat senators spoke at the convention.

  7.If Sarah were a concert pianist for a major orchestra, she would be famous. She is not a concert pianist since she is not famous.

  The conclusion above is unsound because the author does not consider that

  (A) Sarah could be a famous actress.

  (B) Sarah could be a harpist for a major orchestra.

  (C) Sarah could be a pianist with a rock group.

  (D) Sarah could be a concert pianist with a minor orchestra.

  (E) Sarah could be famous for another reason.

  8.Neuroscientists are making progress in discovering more about the cause of Alzheimer’s disease. Alzheimer’s disease patients suffer from dementia and sever memory loss. Autopsies performed on such patients have revealed the presence of brain lesions caused by abnormal protein deposits. Similar deposits are also found in the brains of elderly patients who do not suffer from Alzheimer’s disease. It follows that everyone who lives long enough will eventually develop Alzheimer’s disease.

  Which one of the following statements, if true, most seriously undermines the conclusion that everyone who lives long enough will eventually develop Alzheimer’s disease?

  (A) The lesions found in the brains of non-Alzheimer’s disease patients are far less extensive than those found in the brains of Alzheimer’s disease patients.

  (B) The developing brain produces a greater number of cells than it will ever use. The extra cells are later destroyed by what biologists call “programmed cell death.”

  (C) The procedure that allows scientists to discover the presence of protein deposits during an autopsy is not yet refined enough to ensure detection of the lesions in all patients.

  (D) Autopsies have shown that some people lack the chemical necessary for protein deposits to cause brain lesions.

  (E) Though most Alzheimer’s disease patients develop the disease when they are in their late fifties to early seventies, the frequency of patients who develop the disease in their forties is on the rise.

  9.Free public education is the best form of education there is. Therefore, we must fight to ensure its continued existence; that is, we must be ready to defend the principle of equality of educational opportunity. Because this principle is we worth defending, it is clear that free public education is better than any other form of education.

  Which one of the following illustrates the same weak reasoning as found in the passage?

  (A) I love music, and that’s why I listen to it constantly. I have my stereo or radio on every waking minute. Since I play music all the time, I must really love it.

  (B) Books are my most valuable possessions. My books are like my friends—each pleases me in different ways. Just as I would give up everything to save my friends, so too with my books.

  (C) I would much rather be poor and respected than be rich and despised. To have the respect of others is far more valuable than to have millions of dollars.

  (D) I have never been betrayed by any of my friends. They have been true to me through good times and bad. Therefore I will never betray any of my friends.

  (E) Because every plant I have ever seen has green leaves, I have concluded that all plants must have green leaves. This looks like a plant but it does not have green leaves, so it cannot be a plant.

  10.Some people say that the scarcity of food is a function of the finite limits of the earth’s resources, coupled with a relentless rate of population growth. This analysis fails to recognize, however, that much of the world’s agricultural resources are used to feed livestock instead of people. In the United States, for example, almost one-half of the agricultural acreage is devoted to crops fed to livestock. A steer reduces twenty-one pounds of inexpensive grain to one pound of expensive meat. Thus, the scarcity of food is not merely a function of limited resources and population growth.

  Which one of the following is an assumption that would allow the conclusion in the argument to be properly drawn?

  (A) People prefer eating meat to eating grain.

  (B) Meat is twenty-one times more expensive than grain.

  (C) The limits of the earth’s agricultural resources are not finite.

  (D) More than one-half of the agricultural acreage in the United States is devoted to crops fed to humans.

  (E) Growing crops for human consumption on the acreage currently devoted to crops for livestock will yield more food for more people.