The sun!
I normally don't answer homework questions, but I'll bite on this one. "When rain warms the ocean" is in itself an incomplete sentence. The entire thing is a dependent clause. As constructed, it has no independent clause. However, it could be altered to read "Rain warms the ocean". In that case, the entire sentence is the independent clause.
The type of surface that warms up the slowest is the "ocean" surface.
The North Atlantic Drift is an ocean current that warms France, Ireland and the UK.
Gulf stream
The Gulf Stream.
This process is called conduction, where heat is transferred from the ground to the air through direct contact.
Atlantic
saltier
The gulf stream
Mt. Kilimanjaro is very high. At high altitudes, it gets colder. That is because sunlight warms the ground which warms the air, so air that is very far from the ground tends to be cold. At when it is cold enough, you get snow.
A convection current. The sun warms the ground/sea, this warms the air, the hot air rises, and cold air rushes in to take its place.
Yes, solar radiation warms the surface of the ocean. Warmth rises from the ocean in the form of infrared radiation.