1. What is osmoregulation?
A) Regulation of body temperature
B) Maintenance of water and salt balance in the body
C) Digestion of nutrients
D) Conversion of energy in cells
Answer: B) Maintenance of water and salt balance in the body
2. Which organ is primarily responsible for osmoregulation in humans?
A) Liver
B) Lungs
C) Kidneys
D) Heart
Answer: C) Kidneys
3. What is the functional unit of the kidney that plays a key role in osmoregulation?
A) Alveoli
B) Nephron
C) Villus
D) Axon
Answer: B) Nephron
4. What is the process called where water moves across a semipermeable membrane?
A) Diffusion
B) Osmosis
C) Filtration
D) Active transport
Answer: B) Osmosis
5. Which hormone regulates water balance by increasing water reabsorption in kidneys?
A) Insulin
B) Thyroxine
C) Vasopressin (ADH)
D) Glucagon
Answer: C) Vasopressin (ADH)
6. What is the primary role of the loop of Henle in osmoregulation?
A) Absorption of nutrients
B) Reabsorption of water and salt
C) Secretion of hormones
D) Filtering of blood proteins
Answer: B) Reabsorption of water and salt
7. Marine fish face the challenge of:
A) Gaining too much water from their surroundings
B) Losing water to their hypertonic environment
C) Accumulating excess salt in their bodies
D) Both B and C
Answer: D) Both B and C
8. Freshwater fish osmoregulate by:
A) Drinking large amounts of water
B) Actively absorbing salt through gills
C) Producing concentrated urine
D) None of the above
Answer: B) Actively absorbing salt through gills
9. Which structure in insects helps in osmoregulation?
A) Malpighian tubules
B) Nephridia
C) Flame cells
D) Spiracles
Answer: A) Malpighian tubules
10. In humans, the majority of water reabsorption occurs in the:
A) Bowman’s capsule
B) Proximal convoluted tubule
C) Collecting duct
D) Distal convoluted tubule
Answer: B) Proximal convoluted tubule
11. Terrestrial animals conserve water through:
A) Concentrated urine
B) Moist skin
C) Constant drinking
D) Increased sweat production
Answer: A) Concentrated urine
12. What is a key adaptation in desert animals for osmoregulation?
A) Drinking excessive water
B) Producing dilute urine
C) Efficient water reabsorption in kidneys
D) Using salt glands for excretion
Answer: C) Efficient water reabsorption in kidneys
13. Which nitrogenous waste product requires the least water for excretion?
A) Ammonia
B) Urea
C) Uric acid
D) Creatinine
Answer: C) Uric acid
14. An example of a euryhaline organism is:
A) Goldfish
B) Salmon
C) Frog
D) Earthworm
Answer: B) Salmon
15. What is the role of aldosterone in osmoregulation?
A) Promotes salt reabsorption in kidneys
B) Increases glucose levels in blood
C) Stimulates urine production
D) Enhances water filtration
Answer: A) Promotes salt reabsorption in kidneys
16. Which type of environment poses the greatest challenge for water conservation?
A) Freshwater
B) Marine
C) Desert
D) Polar
Answer: C) Desert
17. What is the main excretory product of amphibians?
A) Ammonia
B) Urea
C) Uric acid
D) Creatinine
Answer: B) Urea
18. Osmoregulation in flatworms is primarily achieved by:
A) Nephridia
B) Malpighian tubules
C) Flame cells
D) Kidneys
Answer: C) Flame cells
19. Which group of animals are osmoconformers?
A) Reptiles
B) Marine invertebrates
C) Mammals
D) Birds
Answer: B) Marine invertebrates
20. What is the condition called when water content in the body decreases significantly?
A) Hyperhydration
B) Dehydration
C) Overhydration
D) Electrolyte imbalance
Answer: B) Dehydration
21. The hormone that inhibits urine production is:
A) Oxytocin
B) Cortisol
C) ADH (Antidiuretic Hormone)
D) Adrenaline
Answer: C) ADH (Antidiuretic Hormone)
22. Animals that excrete ammonia are termed:
A) Ureotelic
B) Uricotelic
C) Ammonotelic
D) None of the above
Answer: C) Ammonotelic
23. The excretory system in earthworms involves:
A) Kidneys
B) Malpighian tubules
C) Nephridia
D) Protonephridia
Answer: C) Nephridia
24. Which organ in birds is specialized for water conservation?
A) Kidney
B) Cloaca
C) Liver
D) Heart
Answer: B) Cloaca
25. Which substance is a major component of the filtrate in Bowman’s capsule?
A) Blood cells
B) Plasma proteins
C) Water and small solutes
D) Fats
Answer: C) Water and small solutes
26. Marine bony fishes maintain osmoregulation by:
A) Drinking seawater and excreting salt through gills
B) Avoiding seawater and relying on fresh sources
C) Producing copious dilute urine
D) Absorbing water through their skin
Answer: A) Drinking seawater and excreting salt through gills
27. What is the primary excretory product of birds and reptiles?
A) Ammonia
B) Urea
C) Uric acid
D) Carbon dioxide
Answer: C) Uric acid
28. Hypertonic urine is produced by the action of:
A) Renin
B) ADH
C) Aldosterone
D) Cortisol
Answer: B) ADH
29. Which adaptation helps freshwater animals prevent excessive water gain?
A) Drinking large amounts of water
B) Producing large amounts of dilute urine
C) Excreting concentrated urine
D) Increasing salt loss through gills
Answer: B) Producing large amounts of dilute urine
30. The primary function of osmoregulation is to:
A) Excrete metabolic wastes
B) Maintain constant body temperature
C) Balance water and electrolytes in the body
D) Regulate blood glucose levels
Answer: C) Balance water and electrolytes in the body
