CBSE Class 12 Biology Assertion & Reason Type Questions 2023: Check Questions, and Answers for Quick Revision

CBSE Class 12 Biology Important Assertion and Reason Type Questions: Practice important assertion and reason type questions from all chapters of class 12 Biology. These assertion type questions are important for the upcoming CBSE Class 12 Biology Board Exam 2023 on March 16, 2023.

CBSE Class 12 Biology Important Assertion and Reason Type Questions 2023: According to the CBSE exam date sheet class 12 Biology 2023 paper is scheduled for March 16, 2023. The paper will have various types of subjective and objective questions covering the syllabus of Class 12 Biology. To get a good score on these questions a student should have a proper hold on the basics and terminologies used in Biology. To help students learn fast and effectively for their upcoming class 12 Biology exam, we are providing here some of the important Biology assertion type questions. You can find the list of class 12 Biology assertion-reason type questions covering major important topics. These assertion type questions are curated by the subject experts after analysing the latest exam pattern and the revised syllabus of Class 12 Biology. All the assertion-reason type questions are provided with answers.

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CBSE Class 12 Biology Important Assertion-Reason Type Questions

These questions consist of two statements each, printed as Assertion and Reason. While answering

these questions, you need to choose any one of the following four responses.

1. If both Assertion and Reason are true and Reason is the correct explanation of Assertion.
2. If both Assertion and Reason are true but reason is not the correct explanation of Assertion.
3. If Assertion is true but Reason is false.
4. If both Assertion and Reason are false.

Question 1: Assertion: The first part of the dicot embryo to appear above ground is the leaf.

Reason: Leaves increase the size of plants.

Answer: C

Question 2: Assertion: Insects visit flowers to gather honey.

Reason: Attraction of flowers prevents the insects from damaging the parts.

Answer: C

Question 3: Assertion-The embryo with 8 to 16 blastomeres is called a morula.

Reason-The morula continuously divides to transform into trophoblast.

Answer: C

Question 4: Assertion- the fertilized egg contains 23 pairs of chromosomes

Reason-zygote is formed by the fusion of egg and the sperm.

Answer: A

Question 5: Assertion: Artificial insemination is the method of introduction of semen inside the female.

Reason: This technique is used in those cases where males have low sperm count.

Answer: A

Question 6: Assertion: In dog flowers F1 plants produce pink flowers.

Reason: It is due to codominance of flower colour alleles with both genes expressing themselves equally.

Answer: C

Question 7: Assertion: Gametes receives only one allele of a gene.

Reason: During gamete formation, mitosis takes place leads to formation of haploid cells.

Answer: C

Question 8: Assertion: A test cross is used to determine the phenotype of an organism.

Reason: F2 generation of a monohybrid test cross produces one or two phenotypes depending upon the genotype of the unknown organism.

Answer: D

Question 9: Assertion- Wings of butterfly and bat show analogy.

Reason- Analogous organs are anatomically different but functionally similar.

Answer: A

Question 10: Assertion -Hardy Weinberg principle explains the occurrence of variation in population and

Species.

Reason- It concludes that disturbances in genetic equilibrium results in evolution.

Answer: D

Question 11: Assertion- Virus infected cells secrete proteins called interferons which protect non -infected cells from further viral infection.

Reason- It is a case of physiological barriers.

Answer: D

Question 12: Assertion- Heroin is an opioid.

Reason- Heroin is obtained from poppy plant.

Answer: B

Question 13: Assertion- Rheumatoid arthritis is an auto-immune disease.

Reason- Here, body attacks self-cells.

Answer: A

Question 14: Assertion: Cyanobacteria like Nostoc and Anabaena are used as biofertilisers.

Reason: Cyanobacteria absorb phosphorus from soil and passes it to crop.

Answer: C

Question 15: Assertion: Saccharomyces cerevisiae is used for making bread.

Reason: Fermentation carried out by Yeast enzymes produces CO2 .

Answer: C

Question 16: Assertion: the double-stranded DNA is denatured by subjecting it to high temperature of 940 C for 15 seconds.

Reason: One of the separated strands of the DNA is destroyed during denaturation and the other act as a template.

Answer: C

Question 17: Assertion: Genetic engineering can overcome the drawbacks of traditional hybridization.

Reason: Genetic engineering can create desired DNA sequences to meet specific requirements

Answer: A

Question 18: Assertion: The process including separation & purification of product are collectively referred as downstream processing

Reason: The downstream processing & quality control testing are same for all type of products.

Answer: C

Question 19: Assertion: Foreign DNA and vector DNA are cut with the help of ligase.

Reason: Ligase act on sugar phosphate backbone of DNA.

Answer: D

Question 20: Assertion: Transgenic animals are used to study the physiology and development of an organism.

Reason: Transgenic animals are specifically designed to allow the study of regulation of genes

Answer: A

Question 21: Assertion: Most food chains and webs have only about four or five trophic levels.

Reason: Trophic efficiencies are generally only about 10% in different ecosystems.

Answer: A

Question 22: Assertion: Pyramid of biomass is always upright for tree ecosystem.

Reason: Total biomass of a tree in a specific area is more than that of herbivores

Answer: A

Question 23: Assertion: Island ecosystems are generally prone to invasion by introduced species.

Reason: Invasion is common when the introduced ecosystem is not similar to the one in which the invader evolved.

Answer: C

Question 24: Assertion: Endemic organisms with limited range are the least affected by habitat destruction.

Reason: These organisms are not found anywhere else within the world and hence have more chance of recovering.

Answer: D

Question 25: Assertion: Tropical rain forests are disappearing fast from developing countries.

Reason: No value is attached to these forests as they are poor in biodiversity.

Answer: C

Question 26: Assertion: A high density of elephant population in an area can result in intra specific competition .

Reason : It plays an important role in supporting other species.

Answer: B

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