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

AI Generated Solution

Promotional Banner

Topper's Solved these Questions

  • ANATOMY OF FLOWERING PLANTS

    TRUEMEN BIOLOGY ENGLISH|Exercise MULTIPLE CHOICE QUESTIONS|192 Videos

  • ANIMAL KINGDOM -NONCHORDATES

    TRUEMEN BIOLOGY ENGLISH|Exercise MCQ|285 Videos

Similar Questions

Explore conceptually related problems

Extra embryonic membrane of the mammals embryo are derived from

Select correct combination of statements for lymph. i. It helps to maintain fluid balance of the body. ii. It is contained in lymphatic vessels and lymphatic organs in mammals. iii.It is derived from tissue fluid. iv. It contains less antibodies than plasma. v. It flows in both directions.

[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 im- pulses to postsynaptic neurons. [R]: The chemical transmitters are called neurohumors which proportionate to K^+ in- flux.

[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 pro- cesses.

A: During evolution pouched mammals of Australia survived. R: Due to lack of competition from any other mammal due to continental drift.

The graph shows the oxygen dissociation curves of haemoglobin from two species of mammals, s and T . Which statements could explain the difference in the oxygen dissociation curves of species S and species T ? I. Species T has higher haemoglobin concentration in its red blood cells than species S. II. The haemoglobin in species T has a lower affinity for oxygen than the haemoglobin in species S. III. Species T may be living at a higher altitudes than species S.

Comprehension # 1 If net force on a system in a particular direction is zero (say in horizontal direction), we can apply: Sigmam_(R )x_(R )= Sigmam_(L)x_(L) , Sigmam_(R )v_(R )= Sigmam_(L)v_(L) and Sigmam_(R )a_(R ) = Sigmam_(L)a_(L) Here R stands for the masses which are moving towards right and L for the masses towards left, x is displacement, v is velocity and a the acceleration (all with respect to ground). A small block of mass m = 1 kg is placed over a wedge of mass M = 4 kg as shown in figure. Mass m is released from rest. All surface are smooth. Origin O is as shown. Normal reaction between the two blocks at an instant when absolute acceleration of m is 5 sqrt3 m//s^(2) at 60^(@) with horizontal is ......... N. Normal reaction at this instant is making 30^(@) with horizontal.

All glands, whether exocrine or endocrine in a mammal, originate from epithelial tissues.

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.

Given a uniform disc of mass M and radius R . A small disc of radius R//2 is cut from this disc in such a way that the distance between the centres of the two discs is R//2 . Find the moment of inertia of the remaining disc about a diameter of the original disc perpendicular to the line connecting the centres of the two discs

TRUEMEN BIOLOGY ENGLISH-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

    |