Answer:
B. It was necessary that each of the two phage components, DNA and protein, be identifiable upon recovery at the end of the experiment.
Explanation:
Hershey and Martha Chase used radiolabeled the DNA of some of the bacteriophage cells with phosphorus (32P). They radiolabeled the sulfur (35S) of the coat protein in the second batch of the phage cells. They infected some of the bacterial cells with phage having radiolabeled DNA while the other <em>E. coli</em> cells were infected with the phage carrying radiolabeled coat protein. This allowed the clear identification of the radiolabelled molecule (DNA or protein) present in the host cell.
They observed that the <em>E. coli </em>cells infected with phage having radiolabeled DNA exhibited the radioactivity while the other batch of the host cell did not show it.
Organisms that reproduce sexually have greater genetic and thus characteristic variations, and so, are able to withstand more selection pressures if they so happen to change or become greater. This increases the chances of survival for that species itself.
Organisms that reproduce asexually are genetically identical to each other. They are unlikely to withstand any changes in selection pressures.
Hope this helps! :)
There are so many examples for that in different areas, like biology experiment carried out in our lab recently.
Here's one link:https://www.creative-biogene.com/support/Knockout-Cell-Lines-in-Antibody-Screening-and-Validation.html
Answer:
D. Changes in the environment changed each morph's ability to evade predation in different ways.
Explanation:
The moth species<em> Biston betularia</em> has two color morphs, or variants. One has a speckled white and black color, while the other is all black. Over the period of time, the distribution of moths dramatically changed between 1900 and 1950 in such a way that black morph became dominant but speckled morphs became very much declined in abundance. The reasons behind this change was heavy industrial pollution in UK between 1900 and 1950.
When the environment became very polluted, dark and blackish, the speckled moth had more chanced of getting eaten by predators thats why they declined in number as compared to black morphs. On the other hand, backgrounds of grime and soot made black morphs less visible to the predators and they survived well. This is an excellent example of natural selection that only those specie better survive that have the ability to cope better with adverse environmental fluctuations.
Therefore, option D is best option.
Hope it help!
