When presented with media messages, americans should keep in mind that a) the first amendment requires that news reports be accurate and free of bias. b) all people should evaluate media messages for accuracy and balance. c) media messages should never be taken seriously. d) propaganda is against the law.

B: all people should evaluate media messages for accuracy and balance.

Explanation:

Americans should keep in mind that not all information that is spread via internet, newspapers, television, magazines, etc. can be considered trustworthy, some can be fake, some can be only personal opinions. Therefore, it is very important to verify the source and the author, also, what  is the purpose for that message.

yes, since there is a positive and a negetive if the positive and negitive wasn't there wouldn't a flow electricity in it.