Free Excretion MCQs with Answers

• A. Osmoconformation
• B. Osmoregulaton
• C. Anhydrobiosis
• D. Anhydrosis

Explanation: Anhydrobiosis is a state in which an organism tolerates extreme dehydration by greatly reducing metabolic activity until water returns.

• A. Stem
• B. Leaves
• C. Flowers
• D. Roots

Explanation: Leaves are called excretophores because plants commonly remove or store wastes in leaves that later fall, carrying those wastes away.

• A. It does not produce waste material
• B. Due to absence of mesoderm
• C. The whole body cells are in contact with water
• D. It has pseudocoelom.

Explanation: Hydra has no specialised excretory organs because its simple body is surrounded by water and its cells can lose soluble wastes directly by…

• A. Creatinine
• B. Trimethyamine oxide
• C. Pyrimidine
• D. Ammonia

Explanation: Ammonia is the simplest nitrogenous waste and is formed when amino acids are deaminated; many aquatic animals excrete it directly because…

• A. Protonephridium
• B. Metanephridium
• C. Malpighian tubules
• D. Nephrons

Explanation: Malpighian tubules are insect excretory organs connected to the gut, where they release nitrogenous waste and help regulate salts and…

• A. Ammonia
• B. Urea
• C. Uric acid
• D. Trimethylamine oxide

Explanation: Earthworms are mainly ureotelic, so their principal nitrogenous waste is urea, although some ammonia may also be excreted depending on…

• A. Nephrostome
• B. Nephridiopore
• C. Flame cell
• D. Anus

Explanation: A nephridiopore is the external opening through which an earthworm's nephridium discharges excretory fluid.

• A. 1 ml
• B. 50 ml
• C. 100 ml
• D. 150 ml

Explanation: Urea requires about 50 mL of water for the excretion of 1 g of nitrogen, so the value is 50 mL per gram of nitrogen.

• A. Stored excretory products in vacuoles, at a concentration that leads to crystal formation.
• B. Accumulate waste in leaves, which fall in autumn.
• C. Production of black wood in the center.
• D. Excrete some of the waste materials directly into soil, occasionally using them as a chemical weapon against other competing plants.

Explanation: Conifers can release certain chemical wastes into the soil through their roots, and some of these substances may inhibit competing plants…

• A. CO2
• B. H2O
• C. O2
• D. Both A and B

Explanation: During autotrophic nutrition, plants carry out photosynthesis and release oxygen as a by-product when water is split during the light…

• A. Hagfish
• B. Jelly Fish
• C. Star Fish
• D. Bony fishes

Explanation: Bony fishes are generally considered to have evolved from freshwater ancestors, although many lineages later adapted to marine…

• A. Osmoconformers
• B. Osmoregulators
• C. Both depend upon the concentration of sea water
• D. None of these

Explanation: Most marine invertebrates are osmoconformers, meaning their internal osmotic concentration changes in close relation to that of seawater.

• A. Increases transpiration by increasing the surface area of the leave.
• B. Small and thick leaves to decrease the surface area proportional to the volume of the leave.
• C. Stomata closing in sufficient supply, and opening in restricted supply of water.
• D. None of these

Explanation: Hydrophytes commonly have broad leaves with a large surface area, supporting rapid transpiration and gaseous exchange in their water-rich…

• A. Protection against micro organisms
• B. Temperature regulation
• C. Excretion
• D. All of these

Explanation: Sebum forms an oily coating that reduces water loss and contains substances that inhibit the growth of microorganisms on the skin, so its…

• A. Flowering plants release chemicals that attract pollinators
• B. A plant releases acid from its roots to destroy competing species
• C. Auxins produced in the apical cells diffuse into the zone of elongation
• D. Carbon dioxide produced in respiration diffuses out of leaves by stomata

Explanation: The correct answer is Option D. Excretion in plants involves the removal of waste products.

• A. Blood of earthworms
• B. Haemolymph of insects
• C. Tissue fluid of flatworms
• D. Interstitial fluid of hydra

Explanation: Malpighian tubules are a type of excretory and osmoregulatory system found in insects and some arachnids.

• A. Creatinine
• B. Ammonia
• C. Urea
• D. Uric acid

Explanation: Excretion is the removal of chemical waste from the body produced by metabolic processes within cells.

• A. Photosynthesis
• B. Ingesiton
• C. Assimilation
• D. Deamination

Explanation: Nitrogenous wastes are produced as a result of "deamination". The breakdown of amino acids releases nitrogen-containing amine groups…

• A. Ammonotelic
• B. Ureotelic
• C. Uricotelic
• D. None of these

Explanation: Different ways of excreting 1 gram of nitrogen require different amounts of water so they are useful for different kinds of animals.

• A. Detoxifies many chemical poisons
• B. Breaks down ammonia for excretion by the kidneys
• C. Produces urea and uric acids from the nitrogen of amino acids
• D. All of the above

Explanation: The liver is an organ that comes into play after consumption of alcohol, as you can remember excess alcohol consumption can result in…