Plasmid DNA play a important role for survival of a prokaryotic cell.
Option D is correct one.
Explanation:
In addition to the chromosome, many prokaryotes have plasmids, which are small rings of double-stranded extra-chromosomal ("outside the chromosome") DNA. Plasmids carry a small number of non-essential genes and are copied independently of the chromosome inside the cell. They can be transferred to other prokaryotes in a population, sometimes spreading genes that are beneficial to survival.
For instance, some plasmids carry genes that make bacteria resistant to antibiotics. (These genes are called R genes.) When the plasmids carrying R genes are exchanged in a population, they can quickly make the population resistant to antibiotic drugs. While beneficial to the bacteria, this process can make it difficult for doctors to treat harmful bacterial infections.
Theses two biomes get very little rain and because of this they have a less diversity of fauna and flora.
The differences are that a tundra is very dry and extremely cold and on the other hand a desert is very arid and hot and it can go as high as 54°C (130°F).
