Download App

Biodiversity and Conservation — BIOLOGY STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 ScienceBIOLOGYBiodiversity and Conservation1 Mark
Question
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: Non-native or exotic species are often introduced in a region for their economic uses.
Reason: Exotic species are considered to be a major cause of extinction of indigenous species.
✓

Answer

  1. Both assertion and reason are true but reason is not the correct explanation of assertion.

Explanation:

The world is facing accelerated rates of species extinctions, largely due to human interference. There are four major causes  - (i) habitat loss and fragmentation, (ii) over-exploitation, (iii) alien species invasions and (iv) co-extinctions.

Non-native or alien species are often introduced inadvertently for their economic and other uses. They often become invasive and drive away the local species. The exotic species are considered to be second major cause of extinction of species (the first being habitat destruction).

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 Biodiversity and Conservation→Biodiversity and Conservation — all question types→BIOLOGY STD 12 Science question papers→Rajasthan Board STD 12 Science question papers→Rajasthan 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.
  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 : Smack is a by-product of heroin synthesis.
Reason: Heroin is an opium alkaloid.
→
Assertion (A): Primer pheromones bring about physiological changes in the receivers.
Reason (R): Releaser pheromones cause immediate change in the receivers.
→
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 : Smoking causes oxygen deficiency in the body.
Reason: Carbon monoxide, when inhaled while smoking, combines with haemoglobin to form chemically stable compound.
→
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: Communities with more species tend to be more stable than those with less species.
Reason: Conununities with more species is not able to resist occasional disturbances.
→
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: Restriction endonucleases recognize short palindromic sequence and cut at specific sites.
Reason: When a restriction endonuclease acts on a palindrome, it cleaves both the strands of DNA molecule.
  1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
  2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
  3. Assertion is correct but Reason is incorrect.
  4. Both Assertion and Reason are incorrect.
→
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: At the time of implantation, which takes place in 14 days, the human embryo is called blastocyst.
Reason: Implantation occurs in the gastrula stage.
→
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: tRNA acts as an adapter molecule.
Reason: tRNA recognizes codon sequence of mRNA during translation.
→
Bt cotton is not:
  1. A GM plant.
  2. Insect resistant.
  3. A bacterial gene expressing system.
  4. Resistant to all pesticides.
→
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 : There is no chance of transmission of malaria to man on the bite of a male Anopheles mosquito.

Reason: It carries a non-virulent strain of Plasmodium.

→