Crossing over is unique to meiosis. Its occurrence depends on specific events early in prophase I and it has important consequences for the rest of meiosis and beyond. Which of the following is a false statement about crossing over: a. For crossing over to occur, homologous chromosomes must align precisely early in prophase I so that nonsister chromatids can exchange corresponding segments of DNA.
b. Crossing over near the centromere occurs much less frequently than crossing over in other chromosomal regions because segments of DNA near the centromeres cannot break and rejoin easily.
c. As a result of crossing over, sister chromatids are no longer identical to each other.
d. Crossing over prevents homologous chromosomes from separating during meiosis I.

Nucleic acid certain protein cell membranes certain carbohydrates

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?

Animals that have thick fur and ae able to store large amounts of body fat live where ?