Question

what drives jet stream formation?
via the magnetic poles pulling air down
the moons gravitational pull on air masses
pressure and temperature gradients where the hadley ferrel and polar cells meet
deep ocean currents effecting the salinity, causing warm waters to move near the surface

Explanation:

Jet - stream formation is mainly driven by pressure and temperature gradients. At the boundaries where different atmospheric circulation cells like the Hadley cell and polar cells meet, significant pressure and temperature differences occur, which drive the formation of jet - streams. Magnetic poles pulling air down, the moon's gravitational pull on air masses, and deep - ocean currents affecting salinity are not the main factors in jet - stream formation.

Answer:

pressure and temperature gradients where the hadley ferrel and polar cells meet