The nervous system is produced by
a. the ectoderm.
b. the endoderm.
c. the mesoderm.
d. the endoderm and ectoderm.
e. all of the germ layers.
Answer: a
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What happens when the cAMP-CAP complex binds the CAP site near the lac promoter?
A. Transcription rate decreases. B. Transcription rate increases. C. RNA polymerase binds to the promoter. D. RNA polymerase binds to the promoter and transcription rate decreases. E. RNA polymerase binds to the promoter and transcription rate increases.
Puppies born too large experience difficulties during birthing and tend to have respiratory and other problems. Puppies born too small often can’t compete with their siblings for their mother’s milk. Thus, puppies of intermediate size have a survival advantage. This is an example of ____ selection.
a. directional b. stabilizing c. disruptive d. frequency e. allelic
The convergence in external morphology of sharks,
penguins, and porpoises is attributed to a. reduced genetic variability in these groups. b. selection pressures that are common to these groups. c. reproductive isolation of these groups. d. identical genes in all three groups. e. use and disuse of the limbs.
________is formed when atom gained or loose electrons.
a. molecule b. isotops c. ions