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1. Organ donation saves lives. 

2. Donate organs today for better tomorrow. 

3. Donate organs – Live after death.

D) Vasopressin not at all released

(C) excretory system

Answer is (A) Kidney

The other excretory organs present in human body in addition to kidney are lungs, skin, liver, large intestine, salivary glands and lacrimal glands.

(B) Through urine test

D) platyhelminthes

(b) Malphigian tubules

1. Plants can get rid of excess water by transpiration and guttation. 

2. The other nitrogenous waste products are stored in leaves, bark and fruits when these dead leaves, bark and ripe fruits fall off from the tree then the waste products in them are removed.

D) Protozoan – Water vascular system

Special excretory organs are absent in amoeba

Through transpiration and guttation plants get rid of excess water.

Some of the nitrogenous wastes produced by various animals other than ammonia, urea and uric acid are:

Jrimethyl amine oxide (TMO) in marine teleosts, guanine in spiders, hippuric acid in mammals, reptiles and other nitrogenous wastes include allantonin, allantoic acid, omithuric acid, creatinine, creatine, purines, pyramidines and pterines.

1. Plants can get rid of excess water by a process like transpiration and guttation. 

2. Waste products may be stored in leaves, bark and fruits.

3. When these dead leaves, bark and ripe fruits fall off from the tree then waste products in them are got rid of. 

4. Plants get rid of carbon dioxide and oxygen through diffusion. 

5. Plants release some waste products through roots also. 

6. Some waste products are deposited near bark as resins or gums. 

7. In many plants waste products are stored in vacuoles of the cells. Plant cells have comparatively large vacuoles.

In porifera and coelenterates water bathes almost all their cells in body of organisms.

1. Uremia is the condition in which kidneys stop working completely and it results in a body being filled with extra water and waste products.
2. The dialysis machine is used to filter the blood of a person whose kidneys are damaged. The process is called ‘hemodialysis.’
3. Kidney transplantation is a permanent solution for renal failure patients.
4. The process of transplantation of organs from brain-dead patients to another is called ‘cadaver transplantation.’ 
5. The first kidney transplantation was performed by Dr. Charles Hufnagel in Washington, the USA in 1954.
6. In India, the first kidney transplantation was done on 1st December 1971 at the Christian Medical College, Vellore, Tamilnadu.

The waste products include carbon dioxide, water, nitrogenous compounds like ammonia, urea, uric acid, bile pigments, excess salts, etc.

The waste products excreted by lungs are carbon dioxide and water.

Answer is (D) B and C

The most poisonous material among nitrogenous waste compounds of human body is ammonia

Substances present in blood are glucose, sodium, potassium chloride, urea, creatinine, uric acid, cholesterol, triglycerides, calcium, phosphorous, bilirubin, proteins, etc.

Ammonia is the most poisonous of all waste products.

1. Different organisms have various excretory systems and organs. 

2. Following are the excretory system found in various organisms.

1. Kidneys remove nitrogenous waste from our body. They also work towards balancing the amount of vitamins , minerals, fat and protein that are found in the blood. They do this so that our body can easily perform day to day activities. 

2. Our intestine makes solid waste materials and is excreted through digestive tract. 

3. Each day our body eliminates around 1.6 to 1.8 liters of urine which contains liquids, minerals and vitamins that are of no use to the body. 

4. The bladder of a human body is nearly the same size as the average of human brain. 

5. In one individuals life span the liver can produce around 184.275 kgs of bile (6500 ounces). 

6. In our lifetime an individual could urinate close to 7,850,000,000 gallons of fluid.

 7. A really extraordinary fact regarding the excretory system is that upto 400 ml of urine can be held in human bladder. 

8. Urine contains a high amount of urea which can be used by plants as a source of nitrogen. Because of this diluted urine can be used in gardens and potted plants. 

9. It is amazing to see that each kidney is made up of approximately more than one million microscopic tubular functional units called nephrons or uriniferous tubules.

1. In human body wastes are excreted not only by kidneys but also by other organs. 

2. Kidney filters blood and eliminates nitrogenous wastes and other harmful things. Filters urea from blood. 

3. Apart from kidney lungs, skin, liver, intestine, salivary glands and lacrymal glands. 

4. Lungs remove carbon dioxide and water in respiration. 

5. Skin excrete wastes in the form of sweat which contains water and certain salts. 

6. Liver eliminates bile pigments bilirubin and biliverdin through urine. 

7. Excess salts of calcium, magnesium and iron are excreted by epithellial cells of colon for elimination along with faeces by intestine.

8. Eccrine glands present on the forehead, the bottoms of the feet and the palms allow excess water to leave the body. 

9. Salivary glands and lacrimal glands excrete small amounts of nitrogenous waste through saliva and tears.

(D) all the above

1. Excretory system in animals performs more than one function. 

2. The primary function of excretory system is to maintain ionic and osmotic balance in the animal body. 

3. Excretory system helps to maintain appropriate concentration of salts and correct amount of water in the body. 

4. It also helps in maintaining the body volume. 

5. The secondary function of excretory system is excretion of nitrogenous wastes and foreign substances such as drugs.

1. Specific excretory organs are absent in unicellular organisms. These organisms remove waste products by simple diffusion from the body surface into the surrounding water. 

2. Excess water is sent out through contractile vacuoles in fresh water protozoans. Ex: Amoeba surface. 

3. The major portion of excess water is eliminated by diffusion through body surface.

The metabolic wastes of haemoglobin of red blood cells in liver are bile pigments like bilirubin, biliverdin and urochrome.

Yes, organisms differ in the type of metabolic wastes they produce. Some organisms excrete ammonia while some excrete urea or uric acid as metabolic wastes.

1. In protozoans wastes are excreted by diffusion through body surface. 

2. Contractile vacuoles present in some protozoans are mainly concerned with the maintenance of osmotic and ionic balance. Excretion is mainly by diffusion. 

3. In sponges, coelenterates like Hydra, excretion takes place by diffusion.

Carbon dioxide, water, nitrogenous compounds like ammonia, urea, uric acid, bile pigments, excess salts, etc., are the wastes produced during metabolic activities.

Oxygen produced in the photosynthesis process is used by all the living organisms on the earth for breathing. Without oxygen life would not be possible on the earth. No organism can survive. Carbon dioxide produced in respiration will be taken up by plants to prepare food materials, in the process of photosynthesis. Plants are called autotrophs because they produce food for ail the animals and human beings directly or indirectly.

C) Both Anabolic & Catabolic activities

The word Excretion belongs to Latin language.

Functions of PCT: 

1. Reabsorbs glucose, amino acids, phosphate, potassium, urea and other organic solutes from the filtrate into the peritubular network. 

2. The PCT regulates pH of the filtrates by exchanging hydrogen ions in the interstitium for bicarbonate ions in the filtrate.

3. It is also responsible to secreting organic acids such as creatinine and other bases into the filtrate. 

4. Proximal convoluted tubule regulates the pH of the filtrate in the kidneys. 

Functions of DCT: 

1. It maintains a proper concentration and pH of the urine. 

2. Extra salts, ions of K⁺, Na⁺, Cl^- and H⁺ secrete from peritubular capillaries into DCT. 

3. It secretes ammonium ions and hydrogen ions. 

4. It is relatively impermeable to water but in the pressure of Antidiuretic hormone.

PCT (Proximal Convoluted Tubule): It is the first part of the renal tubule of Nephron that starts from Bowman’s capsule. Useful substances in primary urine are reabsorbed into the peritubular network.

DCI’ (Distal Convoluted Tubule): It s the last part of the renal tubule of Nephron. In DCT some other wastes like extra salts, ions of K⁺ , Na⁺ , Cl^- and H⁺ are secreted from peritubular capillaries into DCT.

Efferent ArterIole: It is formed from Afferent arteriole. They play an important role in maintaining the glomerular filtration rate.

Parasympathetic nervous system.

Afferent Arteriole: It forms a capillary network called glomerulus inside the Bowman’s capsule. It brings the pressured blood to the glomerulus and the pressure produces the flow of plasma fluids into the tubule.

The process of release of urine from the bladder is called micturition or urination. It is controlled by central nervous system and smooth muscles of sphincter. In young children, micturition cannot be controlled. By toilet training, one can temporarily postpone the signal reaching from the central nervous system to the motor neurons carrying stimuli to the urinary bladder.

(a) 7 

(b) 6 

(c) 5 

(d) 3 

(e) 1 

(f) 2 

(g) 4

If the afferent arteriole of the nephron constricts, GFR is reduced. If the efferent arteriole constricts, GFR is increased.