can someone help me with my physics lab? im very desperate and it needs to get done by tonight. im literally begging.

Why is there friction between objects

The transfer of heat through the movement of a gas or liquid a. convection b. conduction c. radiation

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