Briefly describe how a carbon tax works, discussing the recognized drawbacks and benefits, as well as explaining how it works

Your task is to:

Briefly describe how a  works, discussing the recognized drawbacks and benefits, as well as explaining how it works: who pays, who benefits, why is it effective and efficient, why not;

Briefly describe how a Renewable Portfolio Standard works, discussing the recognized drawbacks and benefits, as well as explaining how it works: who pays, who benefits, why is it effective and efficient, why not;

Discuss which tool would be more politically feasible in the United States, and which would be better for  mitigation