What is the charge of the nucleus of an oxygen atom?
0
–2
+8
+16

The charge will be +8.

How? The atomic number of oxygen is 8 that means that it has 8 protons in it's nucleus. Since each proton has +1 charge on it 8 would have +8.

It's have to be 12 or idk

The answer is water molecules are split.cellular respiration and photosynthesis are complement  reactions to each other. these are reverse reactions. in cellular respiration glucose and oxygen yield water and carbon dioxide. so, when respiration begins,  glucose molecules are split. in the opposite reaction - in photosynthesis, carbon dioxide and water yield glucose and oxygen. thus,  when respiration begins, water molecules are split.