What one advantange of using primary soeces eran doing research on an experiment

What happens in a global convection cell

Imagine that someone pushes one marble toward a motionless marble. would there still be action-reaction forces involved in the collision? how might the marbles’ motions be changed? ?

In which type of system is power held solely by the central government and not shared with regional governments? group of answer choices federal unitary confederate oligarchic