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Sexual Reproduction in Flowering Plants — BIOLOGY STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 ScienceBIOLOGYSexual Reproduction in Flowering Plants1 Mark
Question
For two statements are given-one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.
  1. Both assertion and reason are true, and reason is the correct explanation of assertion.
  2. Both assertion and reason are true, but reason is not the correct explanation of assertion.
  3. Assertion is true, but reason is false.
  4. Both assertion and reason are false.
Assertion: Cross pollination is the only means of pollination in unisexual flowers.
Reason: Self-sterility is the only way to prevent self-pollination in bisexual flowers.
✓

Answer

  1. Assertion is true, but reason is false.

Explanation:

In plants such as hemp and willow where the flowers are unisexual cross pollination becomes obligatory. However, in plants with bisexual flowers legitimate self-pollination is prevented through the various adaptations, such as self-sterility, dichogamy, herkogamy and heterostyly. All those plants in which pollen from a flower is incapable of bringing about fertilization in the same flower are said to be self sterile or self-incompatible.

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