Answer to number 11 (pls i don't wanna retake this class next year, me)

In the light reactions, H2O goes in, and O2 goes out. 

Chlorophyll is the pigment in the chloroplast, so it won't be released.
Nitrogen is not entering the cell, so its lack of release can't be affected.
CO₂ is used in the Krebs cycle, the cycle to the right, and not by chloroplasts.
Oxygen is one of the by-products of photosynthesis, so it would be immediately affected if photosynthesis suddenly stopped.
Thus, the answer is Oxygen