Well mechanical digestion involves physically breaking the food into smaller pieces but chemical digestion involves breaking down into simpler nutrients that can be used by cells.
Mechanical digestion occurs with mastication between teeth and the maneuvering of food into a bolus by the tongue. chemical digestion refers to digestive enzymes secreted in the saliva such as amylase which helps in breaking down protein into smaller subunits.
Synergistic interaction means that the effect of two chemicals taken together is greater than the sum of their separate effect at the same doses. An example is pesticide and fertilizer
