If every oxygen ion (combined with an aluminum ion) has a charge of –2, what must the charge of each aluminum ion be? how can you tell this? also, what has to happen to an uncharged aluminum atom so that it will bond with oxygen?

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.

Which list is in order from simplest to most complex? a bacteria - virus - plant - protist b protist - bacteria - virus - plant c virus - bacteria - plant - protist d virus - bacteria - protist - plant

The two tubes contain bromothymol blue. after 24 hours, what will the color of the water be in tube b? a. green (it won't change) b. yellow c. blue d. colorless (clear)