3. It can be inferred from the passage that Lyme disease has become prevalent in parts of the United States because of which of the following?

　　(A) The inadvertent introduction of Lyme disease bacteria to the United States

　　(B) The inability of modern sanitation methods to eradicate Lyme disease bacteria

　　(C) A genetic mutation in Lyme disease bacteria that makes them more virulent

　　(D) The spread of Lyme disease bacteria from infected humans to noninfected humans

　　(E) An increase in the number of humans who encounter deer ticks

　　4. Which of the following can most reasonably be concluded about the mosquito Aedes albopictus on the basis of information given in the passage?

　　(A) It is native to the United States.

　　(B) It can proliferate only in Asia.

　　(C) It transmits the dengue virus.

　　(D) It caused an epidemic of dengue hemorrhagic fever in the 1950's.

　　(E) It replaced Aedes aegypti in Asia when ecological changes altered Aedes aegypti's habitat.

　　5. Which of the following best describes the organization of the passage?
　   (A) A paradox is stated, discussed and left unresolved.

　　(B) Two opposing explanations are presented, argued, and reconciled.

　　(C) A theory is proposed and is then followed by descriptions of three experiments that support the theory.

　　(D) A generalization is stated and is then followed by three instances that support the generalization.

　　(E) An argument is described and is then followed by three counterexamples that refute the argument.

　　6. Which of the following, if true, would most strengthen the author's assertion about the cause of the Lyme disease outbreak in the United States?

　　(A) The deer population was smaller in the late nineteenth century than in the mid-twentieth century.

　　(B) Interest in outdoor recreation began to grow in the late nineteenth century.

　　(C) In recent years the suburbs have stopped growing.

　　(D) Outdoor recreation enthusiasts routinely take measures to protect themselves against Lyme disease.

　　(E) Scientists have not yet developed a vaccine that can prevent Lyme disease.