Download App

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

Maharashtra 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: Chasmogamous flowers require pollinating agents.
Reason: Cleistogamous flowers do not expose their sex organs.
  • A
    Both assertion and reason are true, and reason is the correct explanation of assertion.
  • ✓
    Both assertion and reason are true, but reason is not the correct explanation of assertion.
  • C
    Assertion is true, but reason is false.
  • D
    Both assertion and reason are false.
✓

Answer

Correct option: B.
Both assertion and reason are true, but reason is not the correct explanation of assertion.
The majority of angiosperms bear chasmogamous flowers, which means the flowers expose their mature anthers and stigma to the pollinating agents. There is another group of plants which set seeds without exposing their sex organs. Such flowers are called cleistogamous and the phenomenon is cleistogamy. Such flowers show self$-$pollination.

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

Similar questions

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.
→
Read the following and answer any four questions from $(i)$ to $(v)$ given below:
The pollen grains or microspores are the male reproductive bodies of a flower and are contained in the pollen sac or microsporangia. Each pollen grain consists of a single microscopic cell, possessing two coats: the exine and the in tine. The exine of a pollen grain is made of chemically stable material. Because of this, pollen grains are often very well preserved for thousands of years in soil and sediments.
  1. One of the most resistant biological material present in the exine of pollen grain is:
  1. Pectocellulose.
  2. Sporopollenin.
  3. Suberin.
  4. Cellulose.
  1. The exine possesses one or more thin places known as:
  1. Raphe.
  2. Germ pores.
  3. Hilum.
  4. Endothecium.
  1. What is the function of germ pore?
  1. Emergence of radicle.
  2. Absorption of water for seed germination.
  3. Initiation of pollen tube.
  4. All of these.
  1. What is the key advantage to the plant for having such strong pollen grain walls?
  1. It protects the vital genetic material in the pollen grain.
  2. It allows pollen to serve as a valuable fossil record for the study of ancient plants.
  3. It prevents the pollen tube from growing out before the pollen grain reaches the stigma of a compatible species.
  4. It gives weight to the pollen grain, allowing it to cling better to the body surfaces of insect pollinators.
  1. The number of germ pores in dicots and monocots respectively are:
  1. One and three.
  2. Three and two.
  3. Two and three.
  4. Three and one.
→
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.
→
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 : Proto$-$oncogenes are cellular genes required for normal growth.
Reason: Under normal conditions, they could lead to the oncogenic transformation of the cell.
→
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: Rhizobium forms nodules on the roots of legume plants.
Reason: Rhizobium fixes atmospheric nitrogen into organic forms which is used by the plant as nutrients.
→
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 : It is considered advantageous to give the polio vaccine orally.
Reason: The oral polio vaccine prevents reinfection by causing intestinal immunity.
→
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: $\text{XX - XY}$ type of sex determination mechanism is an example of female heterogamety and is found in Drosophila.
Reason: Male heterogamety is seen in moths where males produce two different types of gamete.
→
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: Species diversity decreases as we ascend towards high mountains.
Reason: Due to drop in temperature, no seasonal variability occurs in high mountains.
→
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 : Both the passenger and vehicle $\text{DNAs}$ are treated separately with separate restriction endonuclease.
Reason : Ligation is done by the use of alkaline phosphatase and $\text{DNA}$ ligase.
→
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 alcoholic content of fortified wines are high.
Reason: The fermentation is stopped before all the sugars are being converted.
→