If you have an allergic reaction, it means your body cannot handle what you give to it. Say flowers (common) make you sneeze and itch, (like my sister) it is because there's something inside whatever makes you allergic is not good for your body, or your body is not used to it. Can I get a thank you and a rating?
*Hope it helps!!*
Animals, they only have a cell membrane, not cell walls.
I don't know what the answer choices were, though, but I hope this helps.
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.
