Which common halloween vegitable originated in mexico over 9,000 years ago?

Newspaper started by john campbell:

Identify the example of when situation and time are key to assessing risk of harm in a research study: a study on the efficacy of a behavioral intervention for smoking cessation involves both adults and teenagersasking women if they have had an abortionresearch on the prevalence of hiv-infected individuals in communitiesa survey about sexually transmitted diseases

What are the most populous and least areas of russia and why are some areas more heavily populated than others