If a warm air mass and a cold air mass come together which one goes underneath?

The idea of spontaneous generation was disproved by in a experiment involving jars of meat

Astudent reads the following text in a science book: scientific evidence tells us that the cause of earths four seasons is the tilt of earth as it revolves around the sound the student is instructed to illustrate this information in a science book. how will the student illustrate winter in the northern hemisphere? a.earths northern hemisphere will tilt away from the sun. b. earths northern hemisphere will tilt toward the sun. c.earths orbit will be farther away than from the sun d. earths southern hemisphere will tilt away from the sun.

Select all that apply genes are specific nucleotide sequences occur in numbers that are the same as the number of chromosomes are located in a specific place on a chromosome determine the traits of an organism are units of rna