Challenge: the total of the o 2 and co 2 in the test tubes always stayed the same. why do you think this is? (hint molecules of carbon dioxide, co 2 , are made of carbon, c, bonded together with two molecules of oxygen, o.)

Which of the following sex and generation combinations directly produces the pollen tube of angiosperms? a) male gametophyteb) female gametophytec) male sporophyted) female sporophyte

Most of the fossils found in virginia are in the coastal plain, valley, ridge, and appalachian plateau regions, best suggesting that these geographic provinces a) were once covered by seawater. b) are the oldest parts of virginia. c) have a great deal of karst topography. d) have large amounts of sedimentary rock.

How many major plates cover the earth