The earliest vertebrates lacked
A) a notochord. B) gills. C) brains. D) jaws. E) skeletons.
D
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The rRNA gene sequences of hyperthermophilic Archaea and Bacteria have diverged ________ over time, likely due to ________
A) relatively little / strong constraints on sequence changes at higher temperatures B) substantially / higher mutation rates at higher temperatures C) relatively little / low mutation rates in these ancient organisms D) substantially / DNA damage at higher temperatures
At the end of meiosis, the number of chromosomes in each daughter cell is halved because meiosis has
A) two cell divisions after no DNA replication. B) two cell divisions after one DNA replication. C) one cell division after two DNA replications. D) one cell division after one DNA replication.
Define the purpose of cloning a gene into a plasmid cloning vector
What will be an ideal response?
The minimum age of the LUCA (last unique common ancestor) is the age of the oldest fossils that can be identified with certainty as close relatives of present-day prokaryotes and eukaryotes. Such fossils are about ________
A) 3.8 billion years old B) 2 billion years old C) 542 million years old D) 3.28 billion years old E) 65 million years old