Nota Terkini

Tuesday, July 14, 2009

[Science Form 4] Twins

Identical Twins
  • Formation: The fertilisation of an ovum by a sperm forms a zygote, which divides into half and produces two embryos.

  • Placenta: Share the same placenta in the mother's uterus.

  • Genetic make-up: Have the same chromosome make-up.

  • Physical appearance: Usually have similar physical appearances.

  • Sex: Are of the same sex.

Non-identical Twins
  • Formation: The fertilisation of two ova by two sperms, separately.

  • Placenta: Have separate placentas in the mother's uterus.

  • Genetic make-up: Have separate sets of chromosome make-up.

  • Physical appearance: Usually have different physical appearances.

  • Sex: May be of different sexes or the same sex.

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