CBSE 2025 · Region 2 · Set 1 · Q17 · 2 marks
Student to attempt either option (A) or (B) :(i)Write two crucial changes, the seed undergoes while reaching maturity that enable them to be in a viable state until the onset of favourable conditions.(ii)Name the oldest viable seed excavated from Arctic Tundra as per the records.(i)Pea flower produce assured seed sets. Give reason.(ii)In case of Polyembryony, an embryo 'P' develops from a synergid and the embryo 'Q' develops from the nucellus. State the ploidy of embryo 'P' and 'Q'.
Student to attempt either option (A) or (B) :
(i)
Write two crucial changes, the seed undergoes while reaching maturity that enable them to be in a viable state until the onset of favourable conditions.
(ii)
Name the oldest viable seed excavated from Arctic Tundra as per the records.
(i)
Pea flower produce assured seed sets. Give reason.
(ii)
In case of Polyembryony, an embryo 'P' develops from a synergid and the embryo 'Q' develops from the nucellus. State the ploidy of embryo 'P' and 'Q'.
Marking-scheme solution
(i)
The moisture content becomes reduced and the seeds became relatively dry
,the metabolic activity of the embryo slows down (dormancy).
(ii)
Lupinus arcticus / Lupine
(i)
Pea flowers are cleistogamous/ shows autogamy/ carry out self pollination.
(ii)
P- haploid/n , Q- diploid/2n
Sexual Reproduction in Flowering PlantsPost-fertilisation : Structures and EventsUnderstandvery_short_answermedium
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CBSE Class 12 Biology past-paper question from the 2025board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.