What general question would we typically ask several times to determine the root cause of a financial variance?

Which scientific design has both practical limitations and limitations due to scale? studying the effect of bleach on the growth of mold spores exposing cultures of duckweed to different intensities of light observing the replication of dna molecules with a hand lens using colored marbles to model a cross between two colors of rabbits

Eutrophication caused by human nutrient pollution.

At which point is crust neither created nor destroyed? island chain mid-ocean ridge divergent boundary transform boundary