Since cancer is caused by mutations in genes, most mutagens are considered carcinogenic compounds. Thus, a simple test to see whether or not a compound is mutagenic is highly useful. A variation on the mutation rate assay shown below provides a simple assessment of the mutagenic ability of agents. In this variation, two histidine-requiring E. coli cultures are grown in parallel. Both are inoculated into histidine-containing medium. Culture B medium also contains a potential mutagenic agent, while culture A does not. Later, each culture is spread on its own plate on a medium lacking histidine, and cells that can produce their own histidine grow into visible colonies. If culture B is exposed to a mutagen, what is the expected result?
A. Culture B will have more colonies on the histidine-minus plate than culture A.
B. Culture B will have the same number of colonies as culture A.
C. Culture B will not have any colonies at all due to the detrimental nature of mutagens.
D. Culture B will have fewer colonies on the histidine-minus plate than culture A.

The correct answer is option A. "Culture B will have more colonies on the histidine-minus plate than culture A".

Explanation:

In this example, Culture B is a culture of E. coli that has been exposed to a mutagenic agent, therefore it has the potential of developing bacteria that by chance, is able to live in a medium lacking histidine. On the other hand, Culture A is the same E. coli culture but without the exposure to the mutagenic agent. The expected result is that Culture B will have more colonies on the histidine-minus plate than culture A, illustrating that a mutagenic agent can produce E. coli able to reproduce in a histidine-minus plate.

humans can cause extinction of a species through overharvesting, pollution, habitat destruction, introduction of invasive species (such as new predators and food competitors), overhunting, and other influences. explosive, unsustainable human population growth is an essential cause of the extinction crisis.

explanation:

i didn't have the answer choices , but i tried my best.

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