Witch interaction contributes to the greenhouse effect

Which of the following is not a requirement to become a us representative (congressman/congresswoman)? a.be at least 25 years old b.have been a citizen of the united states for the past seven years c.be (at the time of the election) an inhabitant of the state they represent. d.hold a college degree

The information box says that the han added 4,000 miles of wall.refer to the mileage scale.how can this be true?

What are three supporting points as to why opium was wrong in the chinese trade? why should it have stopped? (opium wars)