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How do Organisms Reproduce? — Science STD 10 — Question

CBSE BoardEnglish MediumSTD 10ScienceHow do Organisms Reproduce?5 Marks
Question
Give one example each of unisexual and bisexual flowers. Differentiate between the two types of pollination that occur in flowers. What happens when a pollen lands on a suitable stigma? Write about the events that occur till the seed formation in the ovary.
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Answer

Unisexual Flower: Papaya/Watermelon.
Bisexual Flower: Hibiscus/Rose.
Self-pollination: The pollen grains are transferred from the anther to the stigma of the same flower or to the flower of the same plant.
Cross pollination: The pollen grains are transferred from the anther to the stigma of a flower of a different plant.
  • After pollen lands on a suitable stigma, a pollen tube grows out of pollen grain and travels through the style to reach the ovary.
  • The male germ cell fuses with the female germ cell to form a zygote.
  • Zygote divides several times to form an embryo within the ovule.
  • The ovule develops tough coat and gradually gets converted into a seed.

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