1. How do plants get rid of gaseous wastes generated during photosynthesis or respiration? Plants remove oxygen produced during photosynthesis and carbon dioxide produced during respiration by the process of simple diffusion through stomata and their general body surface 2. How do animals get rid of the gaseous wastes generated during respiration? Animals remove CO2 the gaseous waste generated during respiration by the process of simple diffusion through their respiratory organs like lungs and gills. 3. What are the various types of wastes generated in the body of living organisms? Various types of wastes generated in the body of living organisms are as follows: (i) Digestive wastes generated in the digestive tract during the process of nutrition.
(ii) Photosynthetic wastes in plants
(iii) Respiratory wastes in the form of CO2 gas
(iv) Nitrogenous wastes produced at the end of metabolic processes. 4. What is excretion? Excretion is the biological process involved in the removal of nitrogenous wastes produced during metabolic processes in the body. 5. How do unicellular organisms remove their metabolic wastes? Unicellular organisms remove their metabolic wastes by simple diffusion from the body surface into the surrounding environment.
6. Name the parts of excretory system in human
beings. Human excretory system includes
(1) Pair of kidneys
(2) Pair of ureters
(3) Urinary bladder
(4) Urethra
7. Draw a labelled diagram of human
excretory system.  8. Where are kidneys located in human body? Kidneys are located in the abdominal region, one on either side of the backbone. 9. What is the role of each part of human excretory system? The role of each part of human excretory system is as follows:
(i) Kidneys: They are the main organs of excretion. The nitrogenous metabolic wastes urea is removed from the blood in the form of fluid called urine.
(ii) Ureters: These are the tubes connecting kidneys to urinary bladder. They carry urine from kidney to urinary bladder.
(iii) Urinary bladder: It is the expandable muscular bag which stores urine. When it gets filled with sufficient quantity of urine, the pressure of expanded bladder leads to urge to pass urine out of the body.
(iv) Urethra: It is the tube through which urine is thrown out of the body. 10. Name the basic filtration units present in kidneys. Nephron . 11. Explain the structure of nephron. - Nephron is the basic filtration unit in the kidney
- There are large number of nephrons present in each kidney.
- Each nephron consists of a cup shaped structure called Bowmans capsule at one end.
- The renal artery entering the kidney branches of and these branches enters the Bowmans capsule
- Inside the Bowmans capsule the renal arteriole further branches to form a tuft of capillary cluster called the Glomerulus.
- The Bowmans capsule leads to a long tubular part of nephron.This part is surrounded by a network of capillaries
- At the end of the tubular part is a collecting duct.
- Collecting ducts from all nephrons finally join and connects with the ureter. 12. Draw a labelled diagram of nephron.  | 
