Which of the following is true regarding the polar front jet stream
a. it sometimes requires airlines to allot more time traveling from the east to the west

b. it controls the movement of low pressure systems in north america

c. it is the boundary between cold polar air in the north and warm air to the south

d. all of the above are true

Which continents lie only in the northern hemisphere

If we represent the solar system on a scale that allows us to walk from the sun to pluto in a few minutes, then a) the planets are microscopic and the stars are millions of miles away. b) the planets are the size of basketballs and the nearest stars are a few miles away. c) the planets are marble size or smaller and the nearest stars are thousands of miles away.

Which outcome is not caused by gravitational forcea. gas and dust come together to form a planet b. planets orbit a star c. two atoms come together to form a molecule d. stars cluster to form a galaxy