Answer:
Cu
Explanation:
In the given reaction of the addition of copper to nitric acid,
Cu(s) + 4HNO3(aq) -> Cu(NO3)2(aq) + 2NO2(g) + 2H2O(l)
Cu or copper would be characterized as the reducing agent in this reaction. It is the chemical substance that is losing electrons and being oxidized due to this reduction/loss in this redox reaction as it is the metal that loses electrons by reacting with the non-metals.
I would say the head and heart because if you swim deep in the ocean you will feel pressure in your heart and head because the muscles in your body are closing in on them
hope i helped
The grams of water produced is c