Which source would be most in researching this question?
have helmet laws decreased the number of childhood head injuries?

a. the biography of a professional cyclist whose career ended after a head injury
b. a website featuring an online petition to enact helmet laws in every state
c. a medical journal article titled "cause and treatment of childhood concussions"
d. a newspaper article titled "number of concussions in counties with and without helmet laws"

The correct answer is D. A newspaper article titled "Number of Concussions in Counties With and Without Helmet Laws"

Explanation:

In research, which is the process of solving a problem or question, the word source refers to documents or similar materials such as books, articles or even websites where you can information about the topic the research question is about. This means the source should provide information to answer the question proposed or at least clarify one section of it. In this case the research question is "Have helmet laws decreased the number of childhood head injuries?" which means the author of this research process needs a source that shows the effect of helmet laws have in terms of the number of childhood head injuries or that clarify whether this type of laws can decrease or increase these type of injuries. Because of this, the most helpful source for answering this question is "A newspaper article titled "Number of Concussions in Counties With and Without Helmet Laws" as this will provide information about the number of injuries in areas with helmet laws in comparison to those without helmet law, which is exactly the type of information required for answering the research question proposed.

D). "A newspaper article titled "Number of Concussions in Counties With and Without Helmet Laws."

Explanation:

The source that would prove to be most helpful in researching the given question would be 'A newspaper article titled "Number of Concussions in Counties With and Without Helmet Laws"' as it would propose an authentic and qualitative report reflecting the effects of wearing helmets on road. The article would substantiate the claim/argument statistically which was raised by the given research question that wearing helmets has decreased the number of childhood head injuries and establish the credibility of the author among the audience. Thus, option D is the correct answer.