It decreases. Photosynthesis depends on the availability of light.
http://en.wikipedia.org/wiki/Photosynthesis
This happens mainly due to the lead content in the paints which are mostly used for toys, for small children.
Mostly the leaves
Benthic zone
Chlorenchyma & palisade
Photosynthesis takes place mostly inside the plants leaves as that is where the most chloroplast is kept.
Mostly in plants where they take oxygen and turn it into food which releases carbon dioxide.
cellular respiration for mostly animals cells
Decreased saliva mostly.
Carotenoid
Plants mostly anything that takes in Co2 and realeses oxygen
it mostly happens in El Salvador