Home
Class 12
BIOLOGY
[A] : Origin of mammals is polyphyletic ...

[A] : Origin of mammals is polyphyletic .
[R] : Mammals are derived from atleast two triassic reptilian stocks , Cynodonts and lctidosaurs .

A

If both A and R are true and R is the correct explanation of A

B

If both A and R are true but R is not the correct explanation of A

C

If A is true and R is false

D

If both A and R are false

Text Solution

Verified by Experts

Promotional Banner

Topper's Solved these Questions

  • ANATOMY OF FLOWERING PLANTS

    TRUEMAN BIOLOGY|Exercise MULTIPLE CHOICE QUESTIONS|194 Videos
  • ANIMAL KINGDOM -NONCHORDATES

    TRUEMAN BIOLOGY|Exercise MCQ|291 Videos

Similar Questions

Explore conceptually related problems

Extra embryonic membrane of the mammals embryo are derived from

[A] : In mammals, ends of presynaptic fibres are enlarged to form synaptic Knobs which are separated by a synaptic cleft from postsynaptic neurons. Each synaptic knob contains many mitochondria and small gran- ule-Iike synaptic vesicles filled with minute packets of the chemical that transmits impulses to postsynaptic neurons. [R]: The chemical transmitters are called neurohumors which proportionate to K^+ influx.

[A]: The driving force for passive absorption is non metabolic in origin. [R]: The driving force for active absorption is energy derived from the metabolic processes.

Assertion : In placental mammals the placenta is connected to the embryo by the umblical cord and has an essential role in the immunological protection of the embryo . Reason : In mammals foetal components of the placenta derive initially from the chondroblast connected with embryonic derive initially from he chondroblast connected with embryonic blood stream either through its contact with the yolk sac.

[A] : Placenta is a tissue in eutherian mam- mals that has both embryonic and maternal tissue. [R]: In mammals, foetal components of the placenta derive from trophoblast.

TRUEMAN BIOLOGY-Animal Kingdom -ASSERTION AND REASON
  1. [A] : In the adult bird , only the left ovary is well developed . [R...

    Text Solution

    |

  2. [A] : Rabbit is classified as mammal . [R] : Rabbit possesses mammar...

    Text Solution

    |

  3. [A] : Origin of mammals is polyphyletic . [R] : Mammals are derived...

    Text Solution

    |

  4. [A] : The Ascidian tadpole larva possess all the basic chordate charac...

    Text Solution

    |

  5. [A] : Tail wagging dance is performed for short distances . It conveys...

    Text Solution

    |

  6. [A] : A pair of coxal glands are found in each side of metasoma of sco...

    Text Solution

    |

  7. [A] : Honey bees are social insects known for producing honey and bees...

    Text Solution

    |

  8. Assertion : Cold blooded animals do not have fat layer. Reason : Col...

    Text Solution

    |

  9. [A] : Neoteny is the retention of larval form throughout the life . ...

    Text Solution

    |

  10. [A] : In Parthenogenesis , fertilized egg is stimulated to divide . ...

    Text Solution

    |

  11. [A] : Protozoans have no physiological division of labour . [R] : Th...

    Text Solution

    |

  12. [A] : Visceral leishmaniasis is caused by the sand flies . [R] : Whe...

    Text Solution

    |

  13. [A] : Many desert mammals cool the exhaled air in their noses , befor...

    Text Solution

    |

  14. [A] : Amoeba is regarded as the lowest form of animals. [R] : Body o...

    Text Solution

    |

  15. [A] : In Taenia solium , bladder worm is also known as cysticercus . ...

    Text Solution

    |

  16. Assertion : Bats and whales are classified as mammals Reason : Bats ...

    Text Solution

    |

  17. [A] : The coelomic cavity of Leech is mostly filled with botryoidal ti...

    Text Solution

    |

  18. [A] : When a foreign object , such as a sand grain gets in between the...

    Text Solution

    |

  19. [A] : Tail wagging dance is performed for short distances . It conveys...

    Text Solution

    |

  20. Assertion: The duck-billed platypus and the spiny anteater, both are e...

    Text Solution

    |