Home
Class 12
BIOLOGY
a) Explain the phenomenon of double fert...

a) Explain the phenomenon of double fertilization.
b) Describe the post-zygotic events leading to implantation and placenta formation in humans. Mention any two functions of placenta.

Text Solution

AI Generated Solution

### Step-by-Step Solution #### Part A: Explanation of Double Fertilization 1. **Definition**: Double fertilization is a unique reproductive process that occurs in flowering plants (angiosperms). 2. **Male Gametophyte**: In flowering plants, the male gametophyte, represented by the pollen grain, produces two male gametes. ...
Promotional Banner

Topper's Solved these Questions

  • XII BOARDS

    XII BOARD PREVIOUS YEAR PAPER ENGLISH|Exercise Delhi Board : Set II Section-A|1 Videos

  • XII BOARDS

    XII BOARD PREVIOUS YEAR PAPER ENGLISH|Exercise DELHI BOARD : SET-III (SECTION -A)|2 Videos

  • XII BOARDS

    XII BOARD PREVIOUS YEAR PAPER ENGLISH|Exercise OUTSIDE DELHI: SET III (SECTION A)|2 Videos

  • SAMPLE PAPER 2019

    XII BOARD PREVIOUS YEAR PAPER ENGLISH|Exercise Section E Part B|3 Videos

Similar Questions

Explore conceptually related problems

Mention any four functions of placenta.

State any three functions of placenta in human female.

What is double fertilisation? Describe the process giving its significance. Add a note on post-fertilisation changes leading to the formation of seed.

Explain accelerated europhication. Mention any two consequences of this phenomenon

Explain any two functions of cerebrospinal fluid in humans.

Briefly explain explain the events of fertilization and implantation in an adult human female .

Briefly describe the structre of nucleus and mention its any two function.

Mention the site of fertilization of a human ovum. List the events that follow in sequence until the implantation of the blastocyst.

Given below are diagrams showing the different stages in the process of fertilisation of an egg in the human female reproductive tract. Study the diagrams and answer the questions (i) Arrange the letters given below each diagram in a logical sequence to show the correct order in the process of fertilisation. (ii) Where does fertilisation normally take place? What is 'Implantation' that follows fertilisation ? (iii) Mention the chromosome number of the egg and zygote in humans. (iv) Explain the term 'Gestation'. How long does Gestation last in humans ? (v) Draw a neat, labelled diagram of a mature human sperm.

The diagram given below is that of a developing human foetus. Study the diagram and then answer the questions that follow : (i) Label the parts numbered 1 to 3 in the diagram. (ii) Mention any two functions of the part labelled 2 in the diagram. (iii) Explain the significance of the part numbered 3 in the diagram. (iv) Define the term 'Gestation'. What is the normal gestational period of the developing human embryo? (v) Mention the sex chromosomes in a male and female embryo.

XII BOARD PREVIOUS YEAR PAPER ENGLISH-XII BOARDS-Section -D
  1. Write the name of the organism that is referred to as the "Terror of B...

    Text Solution

    |

  2. a) Draw a labelled diagmmatic view of human male reproductive system. ...

    Text Solution

    |

  3. a) Explain the phenomenon of double fertilization. b) Describe the p...

    Text Solution

    |

  4. A national newspaper reported that a 50 metre high 'Sanitary landfill...

    Text Solution

    |

  5. (a) Draw a diagram of the adult human female reproductive system and l...

    Text Solution

    |

  6. (a) Draw a diagrammmatic sketch of a transverse section of an anther ...

    Text Solution

    |

  7. (a) Why does DNA replication occur in small replication forks and not...

    Text Solution

    |

  8. Draw the pyramids of biomass in sea and in a forest. Explain giving re...

    Text Solution

    |

  9. Describe the roles of heat , primers and the bacterium Thermus aquatic...

    Text Solution

    |

  10. Explain the steps involved in the production of genetically engineered...

    Text Solution

    |

  11. (a) " Oraganisms may be conformers or regulators . " Explain this sta...

    Text Solution

    |

  12. Describe the onter - relationship between productivity , gross primary...

    Text Solution

    |

  13. A national newspaper reported that a 50 metre high 'Sanitary landfill...

    Text Solution

    |

  14. (a) Draw a diagram of the adult human female reproductive system and l...

    Text Solution

    |

  15. (a) Draw a diagrammmatic sketch of a transverse section of an anther ...

    Text Solution

    |

  16. (a) Why does DNA replication occur in small replication forks and not...

    Text Solution

    |

  17. (a) The graph given below represents the organisms response to temper...

    Text Solution

    |

  18. Draw the pyramids of biomass in sea and in a forest. Explain giving re...

    Text Solution

    |

  19. Describe the roles of heat , primers and the bacterium Thermus aquatic...

    Text Solution

    |

  20. Explain the various steps involved in the production of artificial ins...

    Text Solution

    |