(i) The facces initiate a neural reflex causing an urge or desire for its removal.
(ii) The egestion of facces through the anal opening from rectum is called as defaecation.

(i) The caecum is a small blind pouch like structure which opens into the colon (ascending) and it has a narrow finger like tubular projection called vermiform appendix.
(ii) Both the caecum and vermiform appendix are large in herbivorous animals and act as an an important site for cellulose digestion with the aid of symbiotic bacteria.
(iii) Cellulose is converted into bio-cellulose by an enzyme cellulase.

Carbohydrates are sugar and starch. These are the major source of cellular fuel which provides energy. The caloric value of carbohydrate is 4.1 calories per gram and its physiological fuel value is 4 Kcal per gram. Lipids are fats and derivatives of fats, are also the best-reserved food stored in our body which is used for production of energy. Fat has a caloric value of of9.45 Kcal and a physiological fuel value of 9 Kcal per gram.

The food we eat provides energy and organic substances for growth and the replacement of worn out and damaged tissues. It regulates and coordinates the various activities that take place in the body

The saliva contains water, electrolytes (Na⁺, K⁺, Cl^-, HCO₃), salivary amylase (ptyalin), antibacterial agent lysozyme and a lubricating agent mucus (a glycoprotein).