As DNA splits, what is added to the bases on the original strands?*

Which group of chordates does  notpossess true backbones?                 a.  birds      b.  frogs and toads      c.  lampreys      d.  crocodilians

What the theory that the sun goes around earth was replaced with the theory that earth goes around the sun this was an exaple of a

Where do the respiratory and circulatory systems meet? a. in the heart b. in the muscles c. in the lungs d. in the brain