Which of the following systems of trade was most widely used in ancient river civilizations? bartering

b
the exchange of coined money

c
free exchange

d
international trade
HURRY PLZ!!

Dr. redbull conducts a study to determine whether her new energy drink children perform better on spelling tests. she randomly assigns children to one of two groups: group 1 receives her energy drink and group 2 receives water. she then gives both groups a spelling test and compares the results. which of the following is true about this study? a. group 1 is the dependent variable and group 2 is the independent variable. b. this is a correlational study. c. group 2 is the experimental group. d. the independent variable is the type of drink the children receive.

Arthur met rottweiler breeders lynda and george at a dog show in rhode island. the couple, who reside in new york state, later sold several rottweiler dogs to arthur who lived in rhode island. arthur later sued lynda and george, claiming that the dogs were sick and infirm. he filed a complaint in rhode island courts, claiming that even though the dogs were sold in new york, the breeders had attended the dog show and advertised in the rottweiler newsletter which was distributed at the event in rhode island. based on the facts, do you think rhode island courts have personal jurisdiction in this case?

What are policymakers trying to do by using the media to deliver specific messages to citizens?