The precipitate rise in the incidence of type 1 , or juvenile, diabetes, as well as the startling decrease in average age at onset, has led to a nearly commensurate rise in causation hypotheses. The single factor that scientists have most commonly and consistently linked with the rise of cases of type 1 diabetes is weight gain, and, indeed, children's weights are increasing generation by generation, and the greater BMI (body mass index), the younger the child is likely to be at the age of onset. Other factors linked to this rise in incidence and decrease in average of age of onset and tracked with varying degrees of success in recent studies include psychological stress, the increased wealth of the homes in which the children reside, the increased levels of hygiene in the homes in which the children reside, and nourishment by infant formula during 10 the first six months of life. Some of these theories have garnered more academic support than others, but, no matter how much support they have received, correlation is not causation.

The writer mentions greater BMI at earlier ages in this paragraph in order to

A. introduce a common causation hypothesis.
B. provide support for an implied argument.
C. reinforce the importance of a healthful diet for children.
D. provide a possible explanation for the confusion of cause and correlation.
E. cast doubt on studies that collect data on wealth and hygiene.



Which of the following, if it were true, would most seriously weaken the import of a specific data set suggesting a correlation?

A. The average age at onset of type 1 diabetes decreased by one year over a period of just five years.
B. Nourishment by baby formula has not been correlated to a rise in BMI.
C. Among stress factors, only poor performance in school and divorce have been shown to correlate with increased incidence of type 1 diabetes.
D. The incidence of type 1 diabetes is rising at a slower rate among children who are not overweight.
E. There is a higher rate of type 1 diabetes in households with incomes of more than $\$ 80,000$ than in households with lower incomes.




The sentence "Some of these theories...correlation is not causation" serves which of the following purposes in the passage?

A. It provides evidence for an argument against the conclusions previously stated in the passage.
B. It makes an assertion that supports the conclusions previously stated in the passage.
C. It questions the conclusions previously stated in the passage.