Deoxynucleic acid, or DNA is the blueprint of the cell. it has instructions that are needed for the organism to grow, develop, survive and reproduce.
Your nose and your mouth are both a portal of entry into your body. If you cover one and not the other it defeats the purpose because Bacteria can still enter the system. They are both part of your respiratory system.
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.
