One choice contains ONLY biotic factors that might be found in a home aquarium's environment. That is A)
fish, snail, and plants.

B)
fish, snail, and gravel.
water, gravel, and the glass wall of the aquarium.

D)
fish, dissolved oxygen, and bacteria living in the water.

Here's one way to follow the scientific method. place the missing steps in the correct position in the process.

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?

What is used to keep track of the gamates and possible offsprings combination