The respiratory system of cockroach consists of tracheae, tracheoles and spiracles. The main tracheal trunks open to exterior on body surface through 10 pairs of segmentally arranged spiracles. Two pair of spiracles are thoracic (one between pro and mesothorax and other between meso and meta thorax). Eight pairs of spiracle are abdominal (one pair in each of the first eight abdominal segments). Alimentary canal of earthworm is complete and functionally regioned into buccal chamber, pharynx, oesophagus, gizzard, stomach and intestine. Frogs body has two main parts, i.e., head and trunk. Absence of neck and tail provide convenience in both hopping and swimming.