What are some of the sources of generic variations

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.

Question#29: why does the tropical ocean have a greater temperature range than the temperate ocean?

Is becoming less expensive to screen blood samples for dna certain diseases have genetic basis what is possible ethical concern about the availability of inexpensive dna testing