unconstitutionality of Roper v. Simmons

A.  The Court in Roper v. Simmons said it is unconstitutional to execute persons who were 17 at the time of their crimes.  Are persons who are 18 much more responsible than 17-year-olds?  Why draw the line at 17?

B. Briefly summarize the facts, issue, holding and reasoning in the Roper case.

C. How does the Roper case affect the  Graham v. Florida ruling?

Please remember to list your references in Bluebook or APA format.