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

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 : Some diseases that attack in childhood do not attack again.
Reason: Memory cells plays an important role.
→
Directions: In the following questions, the Assertions $(A)$ and Reason$(s) (R)$ have been put forward. Read both the statements carefully and choose the correct alternative from the following:
Assertion: $\text{PCR}$ can detect very low amounts of $\text{DNA}$ and is now routinely used to defect $\text{HIV}$ in suspected $\text{AIDS}$ patient.
Reason: $\text{PCR}$ is a powerful technique to identify many other genetic disorders.
→
Assertion (A): Large holes in Swiss cheese are due to the production of a large amount of carbon dioxide by specific microbe.
Reason (R): The specificity of characteristic texture, flavour and taste of Swiss cheese is due to the use of bacterium Propionibacterium shermanii.
→
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: Hybrids are generally back crossed.
Reason: Back cross is done to increase the traits of the parent.
→
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: Champagne gives off bubbles.
Reason: Alcoholic content is $12-16\%$ in champagne.
→
Assertion (A): Homologous organs have common ancestry and similar functions.
Reason (R): Analogous organs have unlike origin and dissimilar function.
→
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: Alpha diversity refers to species diversity present in a given community or habitat.
Reason: Alpha diversity is expressed by species richness and species evenness in a community or habitat.
→
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: Pollen wall is made up of two walls, the intine and the exine.
Reason: Both the walls have depositions of sporopollenin.
→
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: Aerenchyma is present in the leaves and petioles ofhydrophytes.
Reason: Aerenchyma imparts buoyancy to the hydrophytes.
→
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 : Spleen can be thought of as an immunologic conference centre.
Reason: Spleen helps only in digestion.
→