Three of these processes normally consume oxygen. which process produces oxygen?
a)
combustion
b)
respiration in animals
c)
photosynthesis in plants
d)
operation of an acetylene torch

I think the correct answer from the choices listed above is option C. The process which produces oxygen is the process of photosynthesis in plants. It is very evident in our day to day lives. The oxygen we breath is the product of photosynthesis of plants which is being released to the atmosphere.

By water evaporation from the leaves is created a negative pressure at the top of the tree that promotes the ascension  of the water through channels that are called xylem. there are also two molecule forces that are involved: the intra-water molecules cohesion (water molecules stick to each other) and the adhesion when the water molecules stick to the channels they are running in. this is what enables water to go from the roots to the top of a tall tree.