An unlabeled hierarchical diagram of some astronomical bodies is shown. The labels A, B, C, and D can be used to represent galaxies, solar system, clusters, universe, and planets.

An image of four circles nestled one within the other is shown. The lower boundary of all four circles touch one another. The largest and the outermost circle is labeled A. The next circle in order is labeled B. The next circle is labeled C. The innermost circle is labeled D.

Part 1: Which four astronomical bodies would you choose to represent the four labels in the diagram?
Part 2: Justify your choice based on the hierarchical relationships in astronomical bodies.

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?

Glucose is broken down in different ways, both in the presence and in the absence of oxygen. using the table for reference, what major products are formed in each reaction set?

The first amino acid of a new polypeptide chain is