Photosynthesis Metabolism 47 Physiology 38 Respiration 20 Biochemistry 17 Plant cell 17 Morphology 12 Enzymes 10 Nutrition 9 Proteins 9 Plants 8 Biology 7 Nucleic Acids 7 Plant cells 7 Cell division 6 metabolism 6 Plant physiology 5 Mineral nutrition 4 Botony 3 Fermentation 3 Microbiology 3 Mineral Nutrition 3 Molecular biology 3 Photophysiology 3 Primary productivity (Biology) 3 Toxins 3 carbon metabolism 3 morphology 3 plant productivity 3 Animal nutrition 2