Salinity refers to an increase in the dissolved salt content of a body of water. Salinity has great impacts on the type of organisms that live inside the water. In the question given above, the salinity occurs as a result of non natural influence; since most of the organisms living inside the water before probably have specific optimal salinity range, if the salinity exceed the range they can cope with, they will probably migrate away from the water, those that refuse to migrate will probably die out and new species which can cope with the salinity level will emerge.
Answer:
Option (d).
Explanation:
DNA is the genetic material of all the organism except some viruses. DNA is composed of nitrogenous base, deoxyribose pentose sugar and the phosphate group.
DNA replicatese by semi-conservative mode of replication in which one the daughter DNA consists of one newly synthesized strand and one parental strand. This mode of replication was explained by Messelson and Sthal experiment. The cells from 15N medium are transferred to 14N medium the band of intermediate density was observed. The daughter DNA consists of one 15N DNA strand and one 14N DNA strnd. This strand undergo replication in the 14N medium. This time one low density DNA band ( contains 14N - 14N DNA strand) and one intermediate density band ( 14N-15N DNA).
Thus, the correct answer is option (d).
The period you’ve described would be the G2 phase which is considered a “checkpoint” that determines whether or not a cell can enter the mitosis phase
