The answer to your question is <span> It's a physical system that is not affected by any other system. They don't really exist, other than the universe.
You might incorrectly state that an object is space is isolated from everything else, and it does seem that way. It's still affected by gravitational fields, but negligibly.
However, you look at the universe which you define to be everything ever. There is nothing else that exists to interact with it, so it is an isolated system.</span>
Answer:
Several factors affect the shape of a protein mainly the pH and Temperature surrounding the protein. Changes or unfavourable pH and Temperature could result into protein denaturation
Nitrogen dioxide is covalent, others are ionic. ;)
I believe it is C, there are four nitrogenous bases involved. Adenine, cytosine, guanine, and thymine
