Part 8 — More Complex & Analytical NEET-Oriented MCQs (Q176–200)

Q176.

In frog, which path does oxygenated blood follow?
A. Lungs → Pulmonary artery → Left atrium
B. Lungs → Pulmonary vein → Left atrium ✅
C. Lungs → Pulmonary vein → Right atrium
D. Lungs → Truncus arteriosus → Left atrium

Explanation:

A. Pulmonary artery: Carries deoxygenated blood to lungs.
B. Pulmonary vein → Left atrium (Correct): This is the oxygenated blood pathway.
C. Pulmonary vein → Right atrium: Wrong chamber.
D. Truncus arteriosus: Carries mixed blood away from heart.

Q177.

The cloaca in frogs serves as a common passage for:
A. Urine
B. Feces
C. Gametes
D. All of these ✅

Explanation:

A. Urine: True.
B. Feces: True.
C. Gametes: True.
D. All of these (Correct): Cloaca is a common opening for all.

Q178.

Which structural adaptation helps frogs in both aquatic and terrestrial life?
A. Presence of gills
B. Presence of cloaca
C. Cutaneous and pulmonary respiration ✅
D. Presence of 4-chambered heart

Explanation:

A. Gills: Lost in adult frogs.
B. Cloaca: Not related to dual respiration.
C. Cutaneous + pulmonary respiration (Correct): Enables dual mode.
D. 4-chambered heart: Absent in frogs.

Q179.

Why is frog circulation considered “incomplete double circulation”?
A. It has two atria but one ventricle ✅
B. It has no pulmonary circulation
C. It has no systemic circulation
D. It has no heart valves

Explanation:

A. Two atria + one ventricle (Correct): Blood partially mixes in ventricle.
B. No pulmonary circulation: False.
C. No systemic circulation: False.
D. No valves: False, valves exist in truncus.

Q180.

During amplexus, fertilization in frogs occurs:
A. Inside oviduct
B. In cloaca
C. Outside the female body in water ✅
D. In ovary

Explanation:

A. Oviduct: Not fertilization site.
B. Cloaca: Not correct.
C. In water (Correct): External fertilization is the rule.
D. Ovary: Egg formation occurs, not fertilization.

Q181.

Which system is directly affected if the spiral valve of frog heart is damaged?
A. Excretory
B. Circulatory ✅
C. Nervous
D. Digestive

Explanation:

A. Excretory: Not directly.
B. Circulatory (Correct): Spiral valve directs flow of oxygenated and deoxygenated blood.
C. Nervous: Unrelated.
D. Digestive: Unrelated.

Q182.

Which feature of frog lungs makes them less efficient than mammalian lungs?
A. Lack of alveoli ✅
B. Absence of bronchi
C. Thin walls
D. Presence of mucosa

Explanation:

A. Lack of alveoli (Correct): Frog lungs are simple sacs, less surface area.
B. Absence of bronchi: They have bronchi-like structures.
C. Thin walls: Actually good for diffusion.
D. Mucosa: Not inefficiency factor.

Q183.

What is the functional significance of cutaneous respiration during diving?
A. Allows oxygen uptake underwater ✅
B. Helps in buoyancy
C. Helps in thermoregulation
D. Prevents dehydration

Explanation:

A. Oxygen uptake (Correct): Enables respiration underwater.
B. Buoyancy: Not related.
C. Thermoregulation: Not main function.
D. Prevents dehydration: Opposite, skin must stay moist.

Q184.

Which is the largest organ in frog digestive system?
A. Liver ✅
B. Pancreas
C. Stomach
D. Intestine

Explanation:

A. Liver (Correct): Largest gland, produces bile.
B. Pancreas: Smaller.
C. Stomach: Important but not largest.
D. Intestine: Long, but not largest organ.

Q185.

Which system links excretion and reproduction in male frogs?
A. Nervous
B. Excretory
C. Urinogenital ✅
D. Endocrine

Explanation:

A. Nervous: No direct link.
B. Excretory: Separate function.
C. Urinogenital (Correct): Combines ducts for urine + sperm.
D. Endocrine: Indirect regulation.

Q186.

Which of the following pairs is mismatched?
A. Olfactory lobes – Smell
B. Optic lobes – Vision
C. Medulla oblongata – Involuntary functions
D. Cerebellum – Intelligence ✅

Explanation:

A. Olfactory → Smell: Correct.
B. Optic → Vision: Correct.
C. Medulla → Involuntary actions: Correct.
D. Cerebellum → Intelligence (Correct mismatch): Cerebellum controls balance, not intelligence.

Q187.

What ensures continuous buccopharyngeal respiration in frogs?
A. Moist mucosa and blood supply ✅
B. Presence of alveoli
C. Lungs pumping
D. Muscle contraction in limbs

Explanation:

A. Moist mucosa + blood (Correct): Enables gas exchange.
B. Alveoli: Absent.
C. Lungs: Different respiration type.
D. Limbs: Not related.

Q188.

The renal portal system in frog drains blood from:
A. Intestine → Liver
B. Hind limbs → Kidney ✅
C. Heart → Kidney
D. Lungs → Kidney

Explanation:

A. Intestine → Liver: Hepatic portal.
B. Hind limbs → Kidney (Correct): Renal portal function.
C. Heart → Kidney: Wrong.
D. Lungs → Kidney: Wrong.

Q189.

Which among the following is absent in frog’s blood?
A. RBC
B. Platelets
C. WBC
D. Nucleated RBC in adults ✅

Explanation:

A. RBC: Present.
B. Platelets: Present.
C. WBC: Present.
D. Nucleated RBC in adults (Correct): Frog RBC are nucleated, so the “absent” claim is wrong → This is the trap. ✅ (So correct = None absent, all present).

Q190.

Which structure in frog acts as both excretory and reproductive passage in males?
A. Cloaca
B. Ureter
C. Urinogenital duct ✅
D. Kidney

Explanation:

A. Cloaca: Common opening, not duct.
B. Ureter: Only in females.
C. Urinogenital duct (Correct): Carries both urine and sperms.
D. Kidney: Filters urine, not duct.

Q191.

In frogs, yolk is stored in:
A. Liver
B. Intestine
C. Eggs ✅
D. Ovary

Explanation:

A. Liver: Stores glycogen.
B. Intestine: For digestion.
C. Eggs (Correct): Yolk provides nutrition to embryo.
D. Ovary: Produces eggs, but yolk is inside egg itself.

Q192.

Which of the following ensures unidirectional flow of blood in frog’s heart?
A. Spiral valve
B. Valves in truncus arteriosus ✅
C. Septum
D. Atrium walls

Explanation:

A. Spiral valve: Separates streams.
B. Valves in truncus arteriosus (Correct): Prevent backflow.
C. Septum: Absent in ventricle.
D. Atrium walls: Not valves.

Q193.

The frog’s brain part comparable to human cerebrum is:
A. Olfactory lobe
B. Optic lobe
C. Cerebrum ✅
D. Cerebellum

Explanation:

A. Olfactory: Smell.
B. Optic: Vision.
C. Cerebrum (Correct): Controls voluntary activity, though less developed.
D. Cerebellum: Balance.

Q194.

Which sensory organ is absent in adult frogs?
A. Tympanum
B. Lateral line ✅
C. Eyes
D. Nostrils

Explanation:

A. Tympanum: Present.
B. Lateral line (Correct): Present in tadpoles, absent in adults.
C. Eyes: Present.
D. Nostrils: Present.

Q195.

The pancreas in frogs is located:
A. Between stomach and duodenum ✅
B. Attached to liver
C. Inside cloaca
D. At tip of intestine

Explanation:

A. Between stomach & duodenum (Correct): Location of pancreas.
B. Attached to liver: Liver connects to bile, not pancreas.
C. Cloaca: Wrong.
D. Tip of intestine: Wrong.

Q196.

Which blood vessel carries mixed blood in frog?
A. Pulmonary vein
B. Carotid artery
C. Pulmocutaneous artery ✅
D. Hepatic portal vein

Explanation:

A. Pulmonary vein: Pure oxygenated.
B. Carotid artery: Rich in O₂.
C. Pulmocutaneous artery (Correct): Arises from ventricle with mixed blood.
D. Hepatic portal vein: Deoxygenated from gut.

Q197.

Which hormone regulates metamorphosis in frog?
A. Insulin
B. Thyroxine ✅
C. Adrenaline
D. Oxytocin

Explanation:

A. Insulin: Regulates glucose.
B. Thyroxine (Correct): Initiates metamorphosis.
C. Adrenaline: Stress response.
D. Oxytocin: Mammalian hormone.

Q198.

The excretory waste in frogs is mainly:
A. Ammonia
B. Urea ✅
C. Uric acid
D. Carbon dioxide

Explanation:

A. Ammonia: Excreted by aquatic invertebrates.
B. Urea (Correct): Frogs are ureotelic.
C. Uric acid: Birds and reptiles.
D. CO₂: Expelled by respiration, not excretion.

Q199.

Why do frogs produce a large number of eggs?
A. To ensure survival of species despite external fertilization ✅
B. Because eggs are small
C. Because fertilization is internal
D. Because tadpoles do not hatch

Explanation:

A. Large number ensures survival (Correct): Many lost due to predation/environment.
**B. Egg size not the reason.
**C. Fertilization is external, not internal.
**D. Tadpoles hatch, so wrong.

Q200.

Which feature makes frogs important bio-indicators in ecosystems?
A. Presence of cutaneous respiration ✅
B. Nocturnal lifestyle
C. Oviparous reproduction
D. Poikilothermy

Explanation:

A. Cutaneous respiration (Correct): Sensitive to pollutants, hence indicators of environment.
B. Nocturnal lifestyle: Not related.
C. Oviparous reproduction: Not unique.
D. Poikilothermy: Common in reptiles/amphibians.

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Part 8 — More Complex & Analytical NEET-Oriented MCQs (Q176–200)