Which is the MOST LIKELY location of seafloor spreading

Which process does not require the presence of a physical substance in order to transfer heat? air in the atmosphere is heated by the ground. this warm air then rises, and cooler air falls. this is an example of what type of process? how is conduction different from radiation?

The number to the right of an element's symbol (ex. c-12) identifies the of an isotope.

Do polar molecules have ionic bonds?