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Biology · 2025 · 5 marks
CBSE 2025 · Region 2 · Set 3 · Q31
Student to attempt either option (A) or (B). (A) (i) Give a schematic representation of oogenesis in human females. (ii) Mention the number of…
Student to attempt either option (A) or (B).
(A)(i)
Give a schematic representation of oogenesis in human females.
(ii)
Mention the number of chromosomes at each stage. Correlate the life phases of the individual with the stages of the process.
OR
(B)(i)
Describe the three types of pollination that can occur in a chasmogamous bisexual flower.
(ii)
Draw the diagram of a mature pollen grain released at the two celled stage and label four parts in it.
Marking-scheme solution
(i)
Autogamy – The transfer of pollen grains from the anthers to the stigma of the same flower.
Geitonogamy – The transfer of pollen grains from the anthers of flower to the stigma of another flower of the same plant.
Xenogamy – The transfer of pollen grains from the anthers of a flower to the stigma of another flower on a different plant of the same species
(ii)
All Human Reproduction questions2025 question paperNCERT solutions: Human ReproductionPractice Human Reproduction →
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CBSE Class 12 Biology past-paper question from the 2025 board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.