Awoman gives birth to a son who has type a blood. she has type ab blood. which of the following can be concluded from this about her parents' blood types?

one of her parents had at least one a allele and the other at least one b allele.
one of her parents had type ab blood.
one of her parents had type b blood and the other type a blood.
one of her parents had two a alleles.

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?

Which type of respiration takes place when there is no oxygen present

Natural selection changes allele frequencies because some survive and reproduce more successfully than others.