Carbon dioxide is split to form oxygen gas and carbon compounds

I believe that the correct answer here is:

“in neither photosynthesis nor respiration”

This is because during photosynthesis, carbon dioxide is converted to glucose.

While during respiration, carbon dioxide is not split because it is one of the products of respiration hence it is rather created.

it should be p1 v1 = p2 v2

c. heat could easily travel through the molecules in the air and escape/enter the flask. removing the air slows down the heat transfer.