(i) Ingested food is to be completely digested.
(ii) Digestive medium should become normal conditions.
(iii) Maximum utilization of digestive secretions is to be performed for the digestion of food.
(iv) The stimulation of digestive hormonal secretions is to be regulated.

(i) Liver secretes bile without digestive enzymes.
(ii) Liver secretes bile with the bile salts like sodium taurocholate which serve as antibacterial agents.
(iii) Bile emulsifies and saponifies the fats.
Eg: Weak lipase present with bile in the stomach.

Every tooth in human beings is embedded in a socket in the jaw bone. This type of attachment is called thecodont dentition.

The function of the digestive system is to bring the nutrients, water and electrolytes from the external environment into every cell in the body through the circulatory system.

Plants are autotrophs. They prepare their own food using CO₂ , H₂Oin the presence of sunlight trapped by the chlorophyll pigment present in the leaves. There is no need of digestive system for plants as they use the starch as such.

The food that we eat are macromolecules and in absorbable. These are to be broken down into smaller micro-molecules in absorbable forms. This is done by digestive system.

Test for glucose: Mix the given food sample with 3mL of water in a test tube. Shake the mixture, and then add a few drops of Benedict's solution. Keep the test tube in a water bath and heat carefully. If glucose is present, the colour of the solution will change from blue to green to brick red depending upon the amount of glucose.

Mix the given food sample with 3mL of water in a test tube. Shake the mixture, and then add a few drops of Biuret solution. If protein is present, the colour of the solution will change to purple.

Mouth:
(i) In buccal cavity starch is hydrolysed by saliva.
(ii) The cooked starch (polysaccharide) is converted into a maltose (disaccharide) by salivary amylase or ptyalin.
Duodenum:
Pancreatic amylase converts starch (polysaccharide) into di and monosaccharides.