what is the difference between a multiple-allele trait and a
polygenic trait?

Explanation:

What is the difference between multiple alleles and polygenes? ... Polygenes are a group of (non-epistatic) genes that all control one trait. Multiple alleles are several variant forms of one gene. Polygenes would include the three genes that control skin colour, or the several genes that could influence type 2 diabetes.

as in mitosis, dna replication occurs during interphase.   in meiosis, it occurs specifically in s phase of interphase 1.