BSc Second Year (Sem 3 & 4) Zoology – Daily Revision MCQ (English Medium)
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Amphioxus (Branchiostoma) belongs to which subphylum?
Chapter 1: Protochordata
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Answer: B. Cephalochordata
In Amphioxus the notochord runs the whole length of the body up to the head, the mark of Cephalochordata.The larva of Petromyzon (lamprey) is called:
Chapter 2: Cyclostomata (Petromyzon)
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Answer: A. Ammocoete
Petromyzon has a long-lived filter-feeding larva, the ammocoete, which metamorphoses into the adult.Sharks and other cartilaginous fishes have which type of scales?
Chapter 3: Fishes
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Answer: C. Placoid
Cartilaginous fishes bear placoid scales (dermal denticles), built like tiny teeth with dentine and enamel-like covering.Lampbrush chromosomes are found in:
Chapter 7: Chromosome Structure and Giant Chromosomes
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Answer: B. Diplotene oocytes of amphibians
Lampbrush chromosomes are large, loop-bearing bivalents seen in the diplotene stage of growing oocytes, classically in amphibians; polytene ones are in Drosophila salivary glands.In birds sex is determined by the ZZ–ZW system. Which sex is heterogametic (ZW)?
Chapter 8: Sex Determination and Sex-linked Inheritance
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Answer: D. Female
In birds the female is ZW (produces two kinds of eggs) and the male is ZZ, so the female decides the sex of the offspring.Down syndrome in humans is caused by:
Chapter 10: Human Genetic Disorders
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Answer: C. Trisomy 21
Down syndrome results from an extra copy of chromosome 21 (47, +21); trisomy 13 is Patau, 18 is Edwards, XO is Turner.Among reptiles, a heart with a complete interventricular septum (four chambers) is found in:
Chapter 13: Comparative Anatomy of the Vertebrate Heart
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Answer: C. Crocodile
Crocodilians have two completely separate ventricles; other reptiles have an incompletely divided ventricle.The shift of the oxygen–haemoglobin dissociation curve to the right caused by a rise in CO₂ (and fall in pH) is called:
Chapter 16: Respiration
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Answer: A. Bohr effect
Higher CO₂/H⁺ lowers haemoglobin's affinity for O₂ and helps unloading in tissues; this is the Bohr effect.Based on the tissues separating maternal and foetal blood, the human placenta is:
Chapter 19: Placenta in Mammals
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Answer: D. Haemochorial
In humans the chorion is bathed directly in maternal blood (maternal tissues eroded), so the placenta is haemochorial.Metamorphosis of a frog tadpole into the adult is controlled mainly by:
Chapter 20: Metamorphosis and Regeneration
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Answer: B. Thyroxine
Thyroid hormone (thyroxine) triggers amphibian metamorphosis; ecdysone controls moulting in insects.
BSc Second Year (Sem 3 & 4): MCQ in other subjects
All questions are written by PadhaiNotes in our own words from the common syllabus of Maharashtra universities (NEP). Your own university's syllabus may differ a little.