Respiration and photosynthesis because both happen through the leaves of any plant.
Digestion starts in the mouth when you're chewing, then the stomach, then small intestines.
Just say we have a big amount of tryptophan in the sense that it exceeds, tryptophan would act as a co-repressor which prevents synthesis of more enzymes for its production
Hope this helps :)
Viruses go around in the air and bacteria you have to touch
