Biology [2 Mark Question Answer]

Mendel's law of segregation - It states that "paired factors responsible for a particular character segregate into gametes and recombine during fertilisation."
When gametes are formed, each gamete carries only one factor for a character. It means that the gametes are always pure. Since, the gametes always contain one factor for a character, it is also called the law of purity of gametes.

The sex of a child depends on the father. If the egg containing X-chromosome is fused with Y chromosome bearing sperm at the time of fertilisation, the resulting combination is XY, i.e., the child will be male (son). But when the egg ( X ) is fused with X -chromosome bearing sperm, the child will be a female (daughter).

Mendel selected the garden pea for his experiments in genetics because :
(i) The plant has many varieties, showing a number of contrasting features.
(ii) The plants are easy to cultivate.
(iii) The plant is normally self-pollinating, so he could obtain pure strains.
(iv) Artificial cross-pollination resulted in fertile hybrids.

(i) An unaffected carrier parent can produce affected offspring.
(ii) An affected father can not pass the X -linked recessive disorder to his sons.