Question

which source would be most helpful in researching this question? have helmet laws decreased the number of childhood head injuries? a. a website featuring an online petition to enact helmet laws in every state b. a newspaper article titled number of concussions in counties with and without helmet laws c. the biography of a professional cyclist whose career ended after a head injury d. a medical journal article titled cause and treatment of childhood concussions

Explanation:

The question is about the impact of helmet laws on childhood head - injury numbers. Option A is about a petition, not data on injury numbers. Option C is a biography and not relevant to the impact of laws on injury rates. Option D focuses on causes and treatment, not the impact of laws. Option B directly compares concussion numbers in areas with and without helmet laws, which is most relevant to answering the research question.

Answer:

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