Biology Class 12 Full Course Assertion and reason based Questions

The following questions consist of two   statements, one labelled as Assertion (A) and the other labelled the Reason ®. Examine these two statements carefully and select the most appropriate answer codes.

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

1. Assertion (A): Test cross is used to determine whether the individual is homozygous or heterozygous.
   Reason (R ): In test cross, individual is crossed with the recessive parent.
2. Assertion (A): Industrial melanism is an example of stabilizing selection.
   Reason (R ): Progressive selection favors small or large sized individuals and mean size of the population changes.
3. Assertion (A): Griffith’s experiment proved that DNA is a stable genetic material.
   Reason (R ): In Griffith’s experiment, heat killed the virulent bacteria but did not destroy some of the properties of it’s genetic material.
4. Assertion (A): In Opuntia, leaves are modified into spines.
   Reason (R ): The photosynthetic function is taken over by roots.
5. Assertion (A): Red algae are found in maximum depths as compared to green and brown algae.
   Reason (R ): Only red algae are able to flourish at great depths of sea.
6. Assertion (A): The larvae of pink cotton bollworm enter into diapause in winters.
   Reason (R ): Diapause is influenced by light.
7. Assertion (A): A human population is stable when pre- reproductive and poitu reproductive individuals occupies, a major, a moderate and a few portion of the population, respectively.
   Reason (R ): Below shaped age pyramid is obtained for the stable population.
8. Assertion (A): Natality and immigration contribute to an increase in population density.
   Reason (R ): Natality and immigration both adds new members to a population.
9. Assertion (A): Calotropis a weed, is never browsed by cattle or goats.
   Reason (R ): Calotropis produces highly poisonous cardiac glycosides.
10. Assertion (A): Exponential growth results in a J-shaped curve, when we plot population density in relation to time.
    Reason (R ): In exponential growth, a steady phase is seldom achieved.
11. Assertion (A): Predators play an important role in community.
    Reason (R ): Predators help in maintaining species diversity in a community.
12. Assertion (A): The interaction between fig tree and wasp are mutualistic.
    Reason (R ): The fig tree can be pollinated by any insect.
13. Assertion (A): Parasites are host specific.
    Reason (R ): Many parasites have evolved to go exist in equilibrium with their hosts.
14. Assertion (A): Transgenic mice are used to test the safety of polio vaccine
    Reason (R ): Mouse is the most preferred mammal for studies on gene transfers.
15. Assertion (A): Human insulin can be produced into bacterial cell using biotechnology.
    Reason (R ): To produce human insulin the A, B and C polypeptides of the human insulin are produced separately in the bacterial cells, extracted and combined by creating disulphide bonds.

Answers Sheet

1. B
2. D
3. A
4. C
5. A
6. A
7. D
8. A
9. A
10. B
11. A
12. C
13. A
14. A
15. C