photosynthesis metabolism 20 morphology 15 Plant cell 13 Biochemistry 4 Microbiology 4 Plant physiology 4 Biology 3 Metabolism 3 Physiology 3 genetics 3 Botanical chemistry 2 Botany 2 Cell division 2 Plant growth 2 Production physiology 2 chemosynthesis 2 energetics 2 enzymes 2 fermentation 2 mutation 2 respiration 2 Biochemistry-plant 1 Cell 1 Enviornmental biology 1 Morphology 1 Nitrogen 1 Pathology 1 Photobiology 1 Photophysiology 1