Horizontal pressure gradient forces are generated within thermal circulations because: o cold air rises and warm air sinks. o aloft, high pressure develops in cold air regions while low pressure develops in warm air regions o at the surface, high pressure develops in warm air regions while low pressure develops in cold air regions o in cold regions, isobars bunch closer together, while in warm regions, they spread farther apart

Agroup of students is studying convection currents. they fill two identical balloons with the same amount of helium. one balloon is placed in a freezer and the other in an area with warm air. after 10 minutes, the balloons are released from a height of 1 meter. which of the following do the students most likely observe? a. the balloons both rise. the cold balloon is larger than the warm balloon. b. the balloons rise at the same rate. both balloons are the same size. c. the warm balloon expands and rises. the cold balloon shrinks and sinks. d. the cold balloon expands and rises. the warm balloon shrinks and sinks.

Which of the dna typing techniques do you think you would choose if you had to analyze a dna sample? why?

What method(s) do plants use to obtain nitrogen? select all that apply. absorb it from the atmosphere use bacteria to convert nitrogen to usable form obtain usable nitrogen compounds from the soil absorb nitrogen from water taken in at the roots