What forces are both of these? (F1 and F2)

In a voltaic cell, electrons flow from the (positive/negative) to the (positive/negative) terminal.

Which best describes how fluids change as they travel through different portions of the convection currents? they change to solids at the outer portion of the convection currents. they change to solids at the inner portion of the convection currents. they become more dense at the outer portion of the convection currents. they become more dense at the inner portion of the convection currents

What is friction? how does it affect the motion of an object?