Which of these would most likely change the number of chromosomes found in a cell? A. A pair of chromosomes does not separate when a cell divides. B. A set of chromosomes is duplicated when a cell divides by mitosis.
C. A chromosome in a cell has a sequence of bases altered by a mutation.
D. A pair of chromosomes in a cell overlaps and exchanges genes during meiosis.

Which of the following is a question of morality? a.) delierately reporting false data b.) accidentally reporting false data c.) kepping a sloppy record of experimental observation d.) condition a drug experiment which will harm a lab rats

Keeping in mind the life cycle of bacteriophages, consider the following problem: during the reproductive cycle of a temperate bacteriophage, the viral dna inserts into the bacterial chromosome where the resultant prophage behaves much like a trojan horse. it can remain quiescent, or it can become lytic and initiate a burst of progeny viruses. several operons maintain the prophage state by interacting with a repressor that keeps the lytic cycle in check. insults (ultraviolet light, for example) to the bacterial cell lead to a partial breakdown of the repressor, which in turn causes the production of enzymes involved in the lytic cycle. as stated in this simple form, would you consider this system of regulation to be operating under positive or negative control?

Why are scientists concerned about the depletion of the ozone levels in the stratosphere?