Question

Nitrogenous waste in human beings is
A.Urea
B.Amino acid
C.Fatty acid
D.Ammonia

Answer 1

Hint: In humans , the excretory system consists of a pair of kidney and one pair of ureters and urinary bladder with a urethra . In humans water is limited so a process of excretion in which limited water is required is used . Kidneys are reddish brown bean shaped structures in humans . Kidneys are also used to maintain the internal environment of the body .

Complete answer:
1.Animals accumulate ammonia , urea , uric acid , carbon dioxide , water and ions like sodium , potassium etc. either by metabolic activities or by other means like excess ingestion . This excretory waste is to be removed totally or partially .
2.Ammonia is the most toxic form and requires a large amount of water for its elimination . Whereas uric acid is the least toxic form and can be removed by a minimum loss of water. In human beings urea is excretory waste and can be removed by moderate amounts of water .
3.In humans the main part or the functional and structural part of the kidney are nephrons . Each kidney has nearly 1 million complex tubular structures called nephrons .
4.It begins with the double Walled Cup-like structure called bowman's capsule which encloses the glomerulus . glomerulus along with bowman’s capsule is called the malpighian body or renal corpuscle .
5.The tubules continue to form a highly coiled network proximal convoluted tubule , a henle’s loop and distal convoluted tubule . And a collecting duct is also present .

Hence the correct answer is OPTION(A)

Note: The filtration in humans through Bowman’s capsule is known as ultrafiltration.