Answer:
They used radioactive labeling techniques to build two different types of phage.
Explanation:
In 1952, a set of experiments were carried out by American biochemists Alfred D. Hershey (1908-1997) and Martha Chase. They prepared two separate virus samples, one contained DNA labeled with a radioactive isotope and the other contained protein labeled with a different radioactive isotope. They grew the two types of viruses separately, infected bacteria with the two sets of phages and analyzed the bacteria for radioactivity. From the results obtained, Hershey and Chase concluded that the viral genetic material was DNA and not protein, reinforcing the observations previously made by Avery.
C. ferns.
Explanation:
The ferns are ancient plants that have managed to survive until the present. They are not closely related to the dominant plants nowadays, the flowering plants, but instead they are closely related with plants that have gone extinct tens and hundreds of millions years ago. Even though the ferns are not the dominant plants, they have managed to find a niche and firmly hold onto it, so they remained widespread, normally occupying the lower layers of the forests.
Unlike the flowering plants that produce flowers and then seeds in order to reproduce, that is not the case with the ferns. The ferns actually reproduce through spores, being widely dispersed by the wind and managing to spread out and reproduce over relatively large territory very quickly.
