Which class of gnathostomes is extinct?
a. Sarcopterygii
b. Actinoptertygii
c. Acanthodii
d. Holocephali
c. Acanthodii
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The meteors in meteor showers are believed to be the debris left behind in comet orbits
a. True b. False Indicate whether the statement is true or false
Two parents with type A blood have a child who is type O. The parents' genotypes must be
____________________ and ____________________ or they must have the ____________ phenotype. Fill in the blank(s) with the appropriate word(s).
If living material is produced from living material, the process is called
A. spontaneous generation. B. proteins. C. biogenesis. D. oxidation.
Some anoxygenic photosynthetic bacteria use ________ as their electron source.
A. hydrogen B. hydrogen sulfide C. sulfur D. All of these choices are correct.