Home
Class 12
BIOLOGY
Assertion: Human ancestors never used th...

Assertion: Human ancestors never used their tails and so the tail-expressing gene has disappeared in them.
Reason: Lamarck's theory of evolution is popularly called theory of continuity of germplasm.

A

If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion

B

If both Assertion and Reason are true and the Reason is not the correct explanation of the Assertion.

C

If Assertion is true but the Reason is false.

D

If both Assertion and Reason are false.

Text Solution

Verified by Experts

The correct Answer is:
D
Promotional Banner

Topper's Solved these Questions

  • EVOLUTION

    ICSE|Exercise COMPETITION CORNER (OBJECTIVE TYPE QUESTIONS) (Multiple Choice Questions (MCQs))|55 Videos

  • ENVIRONMENTAL ISSUES

    ICSE|Exercise COMPETITION CORNER (ASSERTION AND REASON TYPE QUESTIONS (FOR AIIMS ASPIRANTS))|9 Videos

  • HUMAN HEALTH AND DISEASE

    ICSE|Exercise COMPETITION CORNER (OBJECTIVE TYPE QUESTIONS) (Assertion and Reason Type Questions (For AIIMS aspirants))|28 Videos

Similar Questions

Explore conceptually related problems

Assertion : Human ancestors never used their tails and so the tails expressing gene has disappeared in them. Reason : Lamarck's theory of evolution is popularly called theory of continuity of germ plasm.

Assertion :- Charles Robert Darwin strongly challanged the ideas of special creation theory. Reason :- Darwin was influenced by idea of use and desuse of lamarck

Assertion:Frog's tadpole has fish-like form, tail and gills Reason: Tadpole stage is the recapitulation of the fish-like ancestor of frog in the latter's life history

Assertion: GM technique has been used to creat tailor made plants to supply alternative resources to industries Reason :Plants, bacteria, fungi & animals whose gene have been altered by mainplulation are called GMO

Niels Bohr a Danish physicist received his PhD from the University of Copenhagen in 1911. He that spent a year with J.J. Thomson and Ernest Rutherford in England. In 1913, he returned to Copenhagen Where he remained for the rest of his life. In 1920 he was named Director of the Institute of theory! Physics After first World War Bohr worked energetically for peaceful uses of atomic energy recieved the first Atoms for Peace award in 1957 Bohr was awarded the Nobel Prize in Physics 1922 (a) The Angular momentum of an electron in a given stationary state can be expressed as m_e vr =h/(2pi) where n=1, 2,3 ...... Thus an electron can move only in those orbits for which its angular momentum is integral multiple of h/2 pi that is why only certain fixed orbits are alowed (b) The radii of the stationary states are expressed as r_n=n^2a_0 where a_0 =52.9 pm. Thus the radius the first stationary state, called the Bohr radius, is 52.9 pm. Normally the electron in the hydrogen atom is found in this orbit (that is n =1). As n increases the value of r will increase (c) The most important property associated with the electron E_n=-2.18xx10^(-18)(Z^2/n^2)J n=1,2,3 (d)it is also possible to calculate to calculate the velocities of electrons moving in these orbits by using v_n=2.18 10^6xxZ/n m/sec. Qualitatively the magnitude of velocity of electron increases with increase of positive charge on the nucleus and decreases with increases the value of n. (e)Bohr's theory can also be applied to th ions containing only one electron, similar to that present it hydrogen atom. For example , He^+ Li^(2+) , Be^(3+) and so on. given by the expression Ex=-218x n=1,2,3 (d) It is also possible to calculate the velocities of electrons moving in these orbits by using V 2.1810 cm/sec Qualitatively the magnitude of velocity of electron increases with increase of positive charge on the nucleus and decreases with increase the value of n (e) Bohr's theory can also be applied to the ions containing only one electron, similar to that presenti hydrogen atom For example, Help, Be and so on Choose the correct statement

Niels Bohr a Danish physicist received his PhD from the University of Copenhagen in 1911. He that spent a year with J.J. Thomson and Ernest Rutherford in England. In 1913, he returned to Copenhagen Where he remained for the rest of his life. In 1920 he was named Director of the Institute of theory! Physics After first World War Bohr worked energetically for peaceful uses of atomic energy recieved the first Atoms for Peace award in 1957 Bohr was awarded the Nobel Prize in Physics 1922 (a) The Angular momentum of an electron in a given stationary state can be expressed as m_e vr =h/(2pi) where n=1, 2,3 ...... Thus an electron can move only in those orbits for which its angular momentum is integral multiple of h/2 pi that is why only certain fixed orbits are alowed (b) The radii of the stationary states are expressed as r_n=n^2a_0 where a_0 =52.9 pm. Thus the radius the first stationary state, called the Bohr radius, is 52.9 pm. Normally the electron in the hydrogen atom is found in this orbit (that is n =1). As n increases the value of r will increase (c) The most important property associated with the electron E_n=-2.18xx10^(-18)(Z^2/n^2)J n=1,2,3 (d)it is also possible to calculate to calculate the velocities of electrons moving in these orbits by using v_n=2.18 10^6xxZ/n m/sec. Qualitatively the magnitude of velocity of electron increases with increase of positive charge on the nucleus and decreases with increases the value of n. (e)Bohr's theory can also be applied to th ions containing only one electron, similar to that present it hydrogen atom. For example , He^+ Li^(2+) , Be^(3+) and so on. given by the expression Ex=-218x n=1,2,3 (d) It is also possible to calculate the velocities of electrons moving in these orbits by using V 2.1810 cm/sec Qualitatively the magnitude of velocity of electron increases with increase of positive charge on the nucleus and decreases with increase the value of n (e) Bohr's theory can also be applied to the ions containing only one electron, similar to that presenti hydrogen atom For example, Help, Be and so on Choose the incorrect curve : if v=velocity of electron in Bohr's orbit r=Radius of electron in Bohr's orbit P.E.=Potential energy of electron in Bohr's orbit K.E.=Kinetic energy of the electron in Bohr's orbit.

ICSE-EVOLUTION-COMPETITION CORNER (Assertion and Reason Type Questions (For AIIMS aspirants))
  1. Assertion: Lederberg's experiment explains the genetic basis of adapta...

    Text Solution

    |

  2. Assertion: Ostrich has vestigial wings and feather but is a cursorial ...

    Text Solution

    |

  3. Assertion: All the animals have three germ layers in their development...

    Text Solution

    |

  4. Assertion: Frog has a fish-like tadpole larva in its life history Re...

    Text Solution

    |

  5. Assertion: All the living organisms have certain basic similarities. ...

    Text Solution

    |

  6. Assertion: Forelimbs of different vertebrates are basically similar. ...

    Text Solution

    |

  7. Assertion: Dinosaurs were connecting links between reptiles and birds....

    Text Solution

    |

  8. Assertion: Many physical and chemical agents induce inheritable mutati...

    Text Solution

    |

  9. Assertion: There is an everlasting competition between individuals hav...

    Text Solution

    |

  10. Assertion: Evolution is adaptation through generations. Reason: Only...

    Text Solution

    |

  11. Assertion: Natural selection is not the exclusive force of speciation....

    Text Solution

    |

  12. Assertion: Human evolution occurred in Asia and Africa. Reason: The ...

    Text Solution

    |

  13. Assertion: Among the primates, chimpanzee is the closest relative of m...

    Text Solution

    |

  14. Assertion: Natural selection is the outcome of differences in survival...

    Text Solution

    |

  15. Assertion: From evolutionary point of view, human gestation period is ...

    Text Solution

    |

  16. Assertion: Amphibians have evolved from fishes. Reason: Archaeopter...

    Text Solution

    |

  17. Assertion: Coacervates are believed to be the precursors of life. Re...

    Text Solution

    |

  18. Assertion: The earliest organisms that appeared on the earth were non-...

    Text Solution

    |

  19. Assertion: The theory of survival of the fittest is widely misundersto...

    Text Solution

    |

  20. Assertion: Human ancestors never used their tails and so the tail-expr...

    Text Solution

    |