Class 12 Biology – Daily Revision MCQ (English Medium)
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The thick outer layer (exine) of a pollen grain is made of a tough, non-biodegradable substance called:
Chapter 1: Reproduction in Lower and Higher Plants
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Answer: D. sporopollenin
Exine is made of sporopollenin, which resists chemicals and does not biodegrade.In human females, fertilization usually takes place in which part of the reproductive tract?
Chapter 2: Reproduction in Lower and Higher Animals
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Answer: A. Ampulla of the fallopian tube
The sperm meets the secondary oocyte in the ampulla of the fallopian tube, where fertilization occurs.Normally, implantation of the embryo occurs in which region of the uterus?
Chapter 2: Reproduction in Lower and Higher Animals
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Answer: B. Fundus
The fundus, the upper dome-shaped part of the uterus, is where the embryo normally implants.The forelimbs of different vertebrates have the same set of bones (humerus, radius-ulna, carpals…) but do different jobs. The differences in such homologous organs are an example of:
Chapter 5: Origin and Evolution of Life
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Answer: B. divergent evolution (adaptive radiation)
Homologous organs show common ancestry; their differences arose by divergent evolution, also called adaptive radiation.Loss of water from a plant in liquid form (guttation) takes place through special structures called:
Chapter 6: Plant Water Relation
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Answer: C. hydathodes (water stomata)
Guttation is loss of liquid water through hydathodes, also called water stomata; transpiration is loss as vapour.The SA node, which acts as the pacemaker of the human heart, is located in the:
Chapter 8: Respiration and Circulation
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Answer: A. right atrium
The SA (sinu-atrial) node lies in the wall of the right atrium and starts each wave of contraction.A healthy adult has a blood pressure of 120/80 mmHg. What is the pulse pressure?
Chapter 8: Respiration and Circulation
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Answer: D. 40 mmHg
Pulse pressure = systolic − diastolic pressure = 120 − 80 = 40 mmHg.The Widal test is used to diagnose which disease?
Chapter 10: Human Health and Diseases
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Answer: C. Typhoid
Typhoid, caused by Salmonella typhi, is diagnosed using the Widal test.In PCR, which enzyme adds nucleotides to extend the primers at about 70–75 °C?
Chapter 12: Biotechnology
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Answer: B. Taq DNA polymerase
Taq DNA polymerase is thermostable, so it works at 70–75 °C to extend the primers (primer extension step).Which one of these is a method of ex situ conservation?
Chapter 15: Biodiversity, Conservation and Environmental Issues
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Answer: D. Seed bank
Ex situ conservation protects species away from their natural habitat, e.g. seed banks; the other three are in situ.
Class 12: MCQ in other subjects
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All questions are written by PadhaiNotes in our own words from the chapters of the official Maharashtra State Board Balbharati textbook (ebalbharati.in). Each question shows its chapter.