Questions 23- 24

The brains of identical twins are genetically identical. When only one of a pair of identical twins is a schizophrenic, certain areas of the affected twin’s brain are smaller than corresponding areas in the brain of the unaffected twin. No such differences are found when neither twin is schizophrenic. Therefore, this discovery provides definitive evidence that schizophrenia is caused by damage to the physical structure of the brain.

23. Which one of the following is an assumption required by the argument?

(A) The brain of person suffering from schizophrenia is smaller than the brain of anyone not suffering from schizophrenia.
(B) The relative smallness of certain parts of the brains of schizophrenics is not the result of schizophrenia or of medications used in its treatment.
(C) The brain of a person with an identical twines is no smaller, on average, than the brain of person who is not a twin.
(D) When a pair of identical twins both suffer from schizophrenia, their brains are the same size.
(E) People who have an identical twin are no more likely to suffer from schizophrenia than those who do not.

24. If the statements on which the conclusion above is based are all true, each of the following could be true EXCEPT:

(A) People who lack a genetic susceptibility for the disease will not develop schizophrenia.
(B) Medications can control most of the symptoms of schizophrenia in most patients but will never be able to cure it.
(C) The brains of schizophrenics share many of the characteristics found in those of people without the disorder.
(D) It will eventually be possible to determine whether or not someone will develop schizophrenia on the basis of genetic information alone.
(E) Brain abnormalities associated with schizophrenia are the result of childhood viral infections that inhibit the development of brain cells.