Final answer:
Mendel's law of segregation states that alleles separate during the formation of gametes, allowing offspring to have an equal chance of inheriting either allele from heterozygous parents and explaining the 3:1 ratio.
Step-by-step explanation:
Mendel deduced the law of segregation, which states that alleles of a gene separate from each other during gamete formation. Gregor Mendel's observations of pea plants led to the formulation of the law of segregation. This fundamental principle of genetics postulates that for any given trait, the pair of alleles (gene variants) inherited from each parent separate during gamete production, or meiosis. Hence, each gamete will carry only one allele for each trait. During fertilization, these alleles can recombine randomly.
This segregation explains why offspring have a 50% chance of inheriting either allele from a pair of heterozygous parents, supporting Mendel's observed 3:1 phenotypic ratio for dominant and recessive traits. The law of segregation is crucial for predicting an offspring's genotype using tools like the Punnett square because it ensures that all possible combinations of parental alleles can be formed during gamete formation.