(i) A well developed respiratory system is found in cockroach compared with other terrestrial (land) insects.
(ii) The respiratory organs 'trachea are branched tubules and open out by 10 paired spiracles or stigmata found in atrium of lateral sides of the body.
(iii) Tracheoles are the tiny terminal branches of trachea found within the body.
(iv) Tracheoles transport respiratory gases like O₂ and CO₂ to the entire body.
(v) The opening and closing of spiracles for the gaseous exchange are regulated by sphincter or spiracular muscles associated with valves.
(vi) Each tracheole is filled with a watery fluid called trachein liquor through which exchange of gases occurs.
(vii) During high muscular activity a part of fluid is drawn into the tissues to enable more O₂ intake and rapid diffusion.
(viii) The passage of air in the tracheal system.
(ix)  Atmosphere  Spiracles  
(x) Trachea  Tracheoles 
(xi) Watery fluid or trachein liquor  Tissues.
(xii) Egress of CO₂ is also supported by striated muscles of body wall as CO₂ is less soluble in trachein liquor.

(i) Ecological imbalance occurs in environment as the frog is the consumer so that frog is to be protected.
(ii) Frog is a carnivore as it feeds on insects and worms. So naturally it reduces insect pest population for the welfare of human beings.
(iii) To control blood pressure and to bring anti-aging properties frogs are used in traditional medicine.
(iv) In USA, Japan, China and North East of India frogs are consumed as delicious food as they have high nutritive value.

The Nervous system of frog is divided into the Central Nervous System [CNS], the Peripheral Nervous System [PNS], and the Autonomous Nervous System [ANS].

Vermiculture, vermicomposting, vermiwash and wormery are inter-linked. and interdependent processes, collectively referred as Vermitech.

A pair of prostate glands lies in the 18^th - 19^th segments. The secretion of the prostate gland serves to cement the spermatozoa into bundles known as spermatophores.