(i) The leech is sangivorous in habit, sucking the blood of cattle and other domestic animals.
(ii) During feeding the leech attaches itself to its victim strongly by the posterior sucker. The leech makes a triradiate or Y shaped incision in the skin of the host by the jaws protruded through the mouth.
(iii) The blood is sucked by muscular pharynx. The salivary secretion is poured.
(iv) The ingested blood is stored in crop chambers and its diverticulum. 
(v) The blood passes from crop into stomach.
(vi) Digestion takes place in stomach by the action of proteolytic enzyme.
(vii) The digested blood is then absorbed slowly by the intestine.
(viii) Undigested food is stored in rectum and egested through anus.
(ix) Leeches prevent blood clotting by secreting a protein called hirudin. They also inject an anaestetic substance that prevents the host from feeling their bite.

(i) Respiration takes place by a pair of lungs, which are light spongy tissues enclosed in the thoracic cavity.
(ii) Each lung is enclosed by a double membranous pleura.
(iii) Atmospheric air passes through the external nostril and nasal passages into the pharynx. From the pharynx it passes through the glottis into the wind pipe.
(iv) The anterior part of the wind pipe is enlarged to form the larynx or voice box with its wall supported by four cartilaginous plates. Inside the larynx lies the vocal cord and its vibrations result in the production of sound.
(v) The larynx leads into trachea or wind pipe. Tracheal walls are supported by rings of cartilage which help in the free passage of air.
(vi) The epiglottis prevents the entry of food into the trachea through the glottis.
(vii) The trachea divides into two branches called the bronchi one entering into each lung and dividing into further branches called bronchioles which end in alveoli.

(i) Teeth are hard bone-like structures used to cut, tear and grind the food materials. The rabbit has two sets of teeth in its life time. The existence of two sets of teeth in the life of an animal is called diphyodont dentition
(ii) In rabbit the teeth are of different types. Hence, the dentition is called heterodont. There are four kinds of teeth in mammals viz. the incisors (I), Canines (C), Premolars (PM) and Molars (M). This is expressed in the form of a dental formula.
(iii) Dental formula is the simple method of representing the teeth of a mammal. The number of each kind of tooth in the upper and the lower jaws on one side is counted
(iv) In rabbit, the dental formula is \(\left( 1\cfrac { 2 }{ 1 } ,C\cfrac { 0 }{ 0 } ,PM\cfrac { 3 }{ 2 } ,M\cfrac { 3 }{ 3 } \right) \) which is written as \(\cfrac { 2033 }{ 1023 } \) Canines are absent.
(v) The gap between the incisors and premolar is called diastema. It helps in mastication and chewing of food - in herbivorous animals.