Final answer:
The physical basis for the segregation of alleles is the separation of homologous chromosomes during anaphase I followed by separation of sister chromatids during anaphase II in meiosis.
Step-by-step explanation:
The physical basis for the segregation of alleles when gametes are formed is c.) separation of homologous chromosomes during anaphase I followed by separation of sister chromatids during anaphase II.
In meiosis, during anaphase I, homologous chromosomes separate, ensuring that each gamete receives one homolog from each pair. Then, during anaphase II, sister chromatids separate, resulting in the production of four different gametic combinations, each containing a haploid set of chromosomes.