The primitive Earth's atmosphere did NOT contain
a. free oxygen.
b. free nitrogen.
c. free hydrogen.
d. water vapor.
e. inert gases.
a
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You are working in a research lab on the organism Drosophila melanogaster and you have been given the job of
determining the relative positions of three linked genes for your undergraduate research project. A graduate student in the lab tells you that gene a is 5.0 centimorgans from gene b, and that gene c is 2.7 centimorgans from gene b. What should you do to finish mapping these three genes? What are the likely results that may occur, and how would you interpret such results?
What will be an ideal response?Which one of the following is the correct classification of vertebrae, from the skull to the pelvis?
A) sacral, coccygeal, lumbar, thoracic, cervical B) cervical, thoracic, lumbar, coccygeal, sacral C) cervical, thoracic, lumbar, sacral, coccygeal D) coccygeal, thoracic, lumbar, sacral, cervical E) coccygeal, thoracic, lumbar, cervical, sacral
Meiosis involves
A) one round of chromosomal replication and one nuclear division. B) one round of chromosomal replication and two nuclear divisions. C) two rounds of chromosomal replication and one nuclear division. D) two rounds of chromosomal replication and two nuclear divisions. E) the number of rounds of chromosomal replication and nuclear divisions depends on whether the cell is haploid or diploid.
A scientist wants to study histones. Histones are
A. proteins that serve as the spindle fiber to pull sister chromatids apart during anaphase. B. proteins that double-stranded DNA molecules wrap around in prokaryotes and eukaryotes. C. proteins that required for the activity of Cdk enzymes. D. proteins that regulate checkpoints in the mitotic cell cycle. E. proteins that double-stranded DNA molecules wrap around in eukaryotes.