This cold river of air travels from west to east in the northern hemisphere. last winter, it dipped far south to bring cold air and snow to many southern states. this is the a) hadley wind. b) polar jet stream. c) arctic jet stream. d) tropical jet stream.

 The answer is polar jet stream because the polar jet stream dips low over the Northern United States during the winter to bring cold air. In the summer, the jet stream retreats and brings cool air to the Northern United States.

Explanation:

compost can be added to topsoil as a:

pesticide

answer; both surfaces of the membrane are nonpermeable