Excretory Structures Across Animal Groups — NEET Biology
📚 Practice ConceptA survey of animal kingdom presents a variety of excretory structures. In most of the invertebrates, these structures are simple tubular forms whereas vertebrates have complex tubular organs called kidneys. Some of these structures are mentioned here. Protonephridia or flame cells are the excretory structures in Platyhelminthes (Flatworms, e.g., Planaria), rotifers, some annelids and the cephalochordate – Amphioxus. Protonephridia are primarily concerned with ionic and fluid volume regulation, i.e., osmoregulation. Nephridia are the tubular excretory structures of earthworms and other annelids. Nephridia help to remove nitrogenous wastes and maintain a fluid and ionic balance. Malpighian tubules are the excretory structures of most of the insects including cockroaches. Malpighian tubules help in the removal of nitrogenous wastes and osmoregulation. Antennal glands or green glands perform the excretory function in crustaceans like prawns.
Consider the following statements : 1. Ammonia is the most toxic form of nitrogenous waste and requires a large amount of water for elimination. 2. Uric acid is the least toxic nitrogenous waste and is removed with maximum water loss. 3. Many bony fishes, aquatic amphibians, and aquatic insects are ammonotelic in nature. 4. Nephridia in annelids help in both nitrogenous waste removal and osmoregulation. 5. Malpighian tubules are the excretory structures of insects like cockroaches and aid in osmoregulation.
View solution & NCERT explanation
Correct answer: A — 1, 3, 4 and 5 are correct
Statement 1 is correct (NCERT: “Ammonia is the most toxic form and requires large amount of water for its elimination”). Statement 2 is incorrect because uric acid is the least toxic and is removed with minimum water loss, not maximum. Statement 3 is correct (bony fishes, aquatic amphibians, aquatic insects are ammonotelic). Statement 4 is correct (nephridia remove nitrogenous wastes and maintain fluid/ionic balance in annelids). Statement 5 is correct (malpighian tubules in insects like cockroaches remove nitrogenous wastes and help in osmoregulation).
What does NCERT say about survey animal kingdom presents?
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Through deep analysis of NEET and NTA, 176 of the 180 ReNEET 2026 (June 21) questions were already in the MedicNEET question bank before the exam.
176/180MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.