Answer:
note: there may be other possible explanations and more body systems can be involved and I can go into much greater detail
1: Nervous system signals your muscles in mouth to abduct and adduct as well as your salivary glands to produce saliva to break down the food, as well as prepare the stomach to digest the food
2: Muscular system moves muscles in mouth to break food down into smaller pieces so there is greater surface area for digestive enzymes to work on the food, then muscles in oesophagus move food to stomach, where stomach muscles churn the broken down food around to speed up digestion
3: Digestive system releases numerous digestive enzymes into the food to break down lipids, carbohydrates and proteins. Small intestines absorb nutrients into bloodstream, and large intestine absorbs water.
4: Excretory system removes excess mostly dry waste through the anus as well as urine from ureter.
