Download App

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: Self-sterility inhibits self-pollination.
Reason: Dichogamy is the condition in which only self-pollination occurs.
✓

Answer

  1. Assertion is true, but reason is false.

​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​Explanation:

Self-sterility is the condition in which the pollen of a flower has no fertilizing effect on the stigma of the same flower. Cross-pollination is thus the only method in them for the production of seeds. In many bisexual flowers, the anther and stigma often mature at different times. This condition is known as dichogamy. Dichogamy often stands as a barrier to self-pollination. There are two conditions of dichogamy.

  1. Protogyny when the gynoecium matures earlier than the anthers of the same flowers.
  2. Protandry when the anthers mature earlier than the stigma of the same flower. In both cases, only cross pollination is possible.

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→Rajasthan Board STD 12 Science question papers→Rajasthan Board question paper generator→

Similar questions

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: Phenylketonuria is a recessive hereditary disease caused by body's failure to oxidise an amino acid phenylalanine to tryrosine, because of a defective enzyme.
Reason: It results the presence of phenylalanine acid in urine.
  1. If both the assertion and the reason are true and the reason is a correct explanation of the assertion.
  2. If both the assertion and reason are true but the reason is not a correct explanation of the assertion.
  3. If the assertion is true but the reason is false.
  4. If both the assertion and reason are false.
  5. If the assertion is false but reason is true.
→
DNA or RNA segment tagged with a radioactive molecule is called _________.
  1. Vector
  2. Probe
  3. Clone
  4. Plasmid
→
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: Infundibulum is a funnel shaped part closer to ovary.
Reason: The edges of infundibulum helps in collection of the ovum after ovulation.
→
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.
  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 : Dendritic cells originate in the bone marrow.
Reason: Dendritic cells are found in neuron.
→
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: Corpus luteum contains blood clot and fibrin.
Reason: Corpus luteum is fanned by the germinal epithelium.
→
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: Whisky develops colour during the aging process.
Reason: Vodka is colourless.
→
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.

  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: Mendel was successful in his hybridisation experiments.

Reason: Garden pea proved to be an ideal experimental material.

→
Assertion (A): The rate of decomposition is controlled by the chemical composition of detritus and climatic factors.
Reason (R): Warm and moist environment does not favour decomposition.
→
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.
  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 : Passive immunity is of short life span.
Reason: Passive immunization is promptly available.
→
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.
  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: Amensalism is a negative interaction between two living individuals.
Reason: In amensalism, allochemics are secreted by one individual.
→