Not to be too picky, but the question ought to say a positively charge ion rather than atom.
I will assume that is what you mean. An ion, using ordinary means, will be positive if it loses electrons (which are negative).
An ion can never gain protons. Left alone, the nucleus will remain unchanged for the rest of eternity. D is wrong.
C is wrong. If electrons are gained, the ion will go negative.
B is wrong for the same reason D is. An ion can't gain protons and it can't lose them.
A is the answer.
Non point source pollution is a greater threat than point source pollution because non point source pollution disrupts the water cycle.
Osmosis! Osmosis is the process that water diffuses across the plasma membrane.
If all nations agreed to reduce global warming then It would be good because the seals need icy conditions. So the less global warming then the more icy habitats there will be and the seals will have more places to live.
Hope this helps
Answer: peptide bonds
Explanation: I think that's the answer.