What is the main organ for gas exchange in fish?
a. Lungs
b. Respiratory system
c. Gills
d. Heart
Ans: c. Gills
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Explain why HIV becomes resistant so quickly when a single drug is used therapeutically
A. The virus is an RNA genome virus-by using host RNA polymerase to directly copy the genome to make more virus particles, there's no proofreading capability. This leads to a high rate of mutation of the viral genome and increased chance for drug resistance. B. HIV utilizes reverse transcriptase to make a cDNA version of its RNA genome. This polymerase is "'sloppy," with a high rate of error and lack of a proofreading capability. This leads to a high rate of mutation of the viral genome and increased chance for drug resistance. C. HIV synthesizes a protein enzyme that directly cleaves anti-HIV drugs, giving it a characteristically high rate of resistance to a single drug type. D. HIV is constantly changing its genetic structure by swapping genetic elements with other virus strains. This leads to a high rate of mutation of the viral genome and increased chance for drug resistance.
The cellular fragments in the blood that function in blood clotting are
a. erythrocytes. b. leukocytes. c. platelets. d. none of the above.
Transformation in a cloning experiment is ________
A) ligating pieces of foreign DNA together B) inserting DNA into bacteria cells C) cutting DNA with restriction enzymes D) using PCR to clone a gene E) a technique for determining gene copy number in a genome
Chalk deposits are formed from the ancient remains of apicomplexans
Indicate whether the statement is true or false