What is the predominant hypothesis for why animals only appeared in the fossil record about 3 billion years after life originated?
A. There were animals 3 billion years ago;
they just weren't fossilized.
B. Animals are warm-blooded; the ocean was
too cold for animals to evolve 3 billion years
ago.
C. Animals have higher metabolisms, and
animal diversification and evolution didn't
really happen until there was sufficient
oxygen in the atmosphere.
D. Animals are heterotrophic and couldn't
evolve until there were enough
photosynthetic organisms on Earth to support
being eaten by animals.
C
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How is a typical prokaryotic genome similar to a eukaryotic genome?
A. Both are composed of DNA packaged in the nucleus. B. Both are composed of double-stranded DNA. C. Both are composed of circular chromosomes. D. Both are composed of multiple, linear chromosomes. E. Both contain chromosome with a single origin of replication.
Which of the following statements about hair cells is NOT true?
A. They are found in the mammalian ear. B. They are found in the fish lateral line system. C. They can be repaired if they rupture. D. Bending of the cells triggers ion flow across the cell membrane. E. Their structure includes stereocilia and a kinocilium.
An anticodon
(a) is a three-base sequence of nucleotides on tRNA. (b) is produced by translation of RNA. (c) has the same base sequence as does the codon. (d) is the same as a gene.
In a Punnett square, the letters within the little boxes
represent a. offspring genotypes. b. parental genotypes. c. gametes. d. offspring phenotypes. e. parental phenotypes.