Select incorrect sentence for down's syndrome

  • A

    Chromosomal disorder

  • B

    Trisomy of $21^{th}$ pair

  • C

    Mental development is retarded

  • D

    It occurs due to crossing over

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A cell at telophase stage is observed by a student in a plant brought from the field. He tells his teacher that this cell is not like other cells at telophase stage. There is no formation of cell plate and thus the cell is containing more number of chromosomes as compared to other dividing cells. This would result in

  • [NEET 2016]

Describe chromosomal disorder and describe its examples.
 

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