Download App

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

Gujarat BoardEnglish MediumSTD 12 ScienceBIOLOGYSexual Reproduction in Flowering Plants1 Mark
MCQ
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.
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.
  • A
    Both assertion and reason are true, and reason is the correct explanation of assertion.
  • B
    Both assertion and reason are true, but reason is not the correct explanation of assertion.
  • ✓
    Assertion is true, but reason is false.
  • D
    Both assertion and reason are false.
✓

Answer

Correct option: C.
Assertion is true, but reason is false.
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.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "Assertion (A) & Reason (B) MCQ" from Sexual Reproduction in Flowering Plants→Sexual Reproduction in Flowering Plants — all question types→BIOLOGY STD 12 Science question papers→Gujarat Board STD 12 Science question papers→Gujarat Board question paper generator→

Similar questions

Assertion (A): Reproductive health means total well-being in all aspects of reproduction, i.e., physical, emotional, behavioural, and social.
Reason (R): A society with people having physically and functionally normal reproductive organs might be called reproductively healthy.
→
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.
Assertion: The concept of one gene$-$one enzyme was changed to one gene$-$one polypeptide.
Reason: Each enzyme may consist of two or more different polypeptides.
→
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.
Assertion: Allogamy includes both geitonogamy and xenogamy.
Reason: Allogamy needs abiotic or biotic external agencies for pollination.
→
For question 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.
Assertion: Amensalism is a negative interaction between two living individuals.
Reason: In amensalism, allochemics are secreted by one individual.
→
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.
Assertion : Inflammatory response is produced in the body after some infections.
Reason: This is one type of defence mechanism.
→
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.
Assertion: Nucellus functions as a nutritive tissue.
Reason: Nucellus is always exhausted completely during development of embryo sac.
→
Assertion (A): Homo sapiens have evolved from chimpanzee-like ancestors.
Reason (R): There is no difference between the two in the amino acid sequence of the protein Cytochrome-C.
→
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.
Assertion: Initiation step of protein synthesis in prokaryotes and eukaryotes has several differences.
Reason: They both form $\text{mRNA - tRNA}$ complex with smaller subunit of ribosome.
→
For question 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.
Assertion: Indiscriminate exploitation ofeconomically important wild plants may lead to their extinction.
Reason: Non$-$conservation of their germplasm is responsible for this.
→
For question 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.
Assertion: Many plants growing in oli gotroph ic soi Is possess mycorrhizae.
Reason: Mycorrhizae help in efficient absorption of nutrients.
→