Explain the Law of Segregation using an example of a monohybrid cross involving flower color in pea plants (Purple is dominant over white).

The Law of Segregation states that during the formation of gametes, the two alleles for a heritable character segregate (separate) from each other such that each gamete receives only one allele. 

For example, if we cross a pure-breeding purple-flowered pea plant (PP) with a pure-breeding white-flowered pea plant (pp), the F1 generation will all be heterozygous purple (Pp). 

When these F1 plants form gametes, the 'P' allele and the 'p' allele segregate, so that half the gametes will carry 'P' and half will carry 'p'. This segregation ensures that the recessive trait (white flowers) reappears in the F2 generation when two F1 individuals are crossed (Pp x Pp), resulting in a 3:1 phenotypic ratio (3 purple: 1 white).