Members of the phylum Chordata have ________ just behind their mouths that extend to the outside environment.
a. book gills
b. pharyngeal slits
c. tonsils
d. madreporites
b. pharyngeal slits
Members of the phylum Chordata have pharyngeal slits just behind their mouths that extend to the outside environment. In organisms that live in aquatic environments, they allow for the exit of water that enters the mouth during feeding. In jawed fishes, they appear as gills, and in tetrapods, they are modified into parts of the ear and tonsils.
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Nondegradable
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The bird-rhino relationship is an example of ________
A) parasitism B) mutualism C) predator-prey D) commensalism
Divergence time estimates based on molecular clocks are
A) best interpreted with caution, since they depend on assumptions that are difficult to test. B) likely to be correct regardless of the genes used or the groups of organisms. C) more reliable than divergence dates that are based on analysis of the fossil record.
T lymphocytes mature in the (bone marrow/lymph node/thymus)
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