(i) Each human cell contains 23 pairs (46) chromosomes. Out of 23 pairs 22 pairs are autosomes. The last 23rd pair is allosome or *** chromosome.
(ii) The chromosomes in males are 2 types, i.e., X and Y. So chromosomes in males are XY. These two chromosomes determine the *** of an individual.
(iii) Females have two types of allosomes. They are X and X. *** chromosomes of fema-les are XX.
(iv) All the gametes (ova) produced by a woman have only X-chromosomes. The gametes (*****) produced by a man have both X and Y chromosomes.
(v) If the ***** carries Y-chromosome and fertilizes the ovum (X), then the baby will have XY. So the baby will be a boy.
(vi) If the ** carries X chromosome and fertilises with X chromosome of ovum, the baby will be a girl. Hence, only father decides the of the baby.
