19. At which developmental stage should one be able to first distinguish a protostome embryo from a deuterostome embryo? (A) coelom formation (B) metamorphosis (C) fertilization (D) cleavage (E) gastrulation

16. A principal problem with inserting an unmodified mammalian gene into a plasmid and then getting that gene expressed in bacteria is that _____. (A) bacteria translate only mRNAs that have multiple messages (B) prokaryotes use a different genetic code from that of eukaryotes (C) bacteria cannot remove eukaryotic introns (D) bacterial RNA polymerase cannot make RNA complementary to mammalian DNA

19. At which developmental stage should one be able to first distinguish a protostome embryo from a deuterostome embryo?
(A) coelom formation
(B) metamorphosis
(C) fertilization
(D) cleavage
(E) gastrulation

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