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**20 points**

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

How can antibodies "remember" a particular bacterial invader or "antigen" on that invader?

The embryos of a bird, a reptile, and a mammal are similar in appearance. how does comparing the physical appearance of embryos of different species support the theory of evolution? a. it shows that these organisms share a common ancestor. b. it provides evidence that these organisms eat the same foods.c. it shows that these organisms share the same habitat.d. it provides evidence that these organisms suffered a genetic mutation.