Question

How does crossing over, the distribution of random mixes of homologous chromosomes into gametes, and fertilization all contribute to variation in the traits of offspring?

Answer 1

Crossing over contributes to variation in an offspring's traits by distributing random mixes of homologous chromosomes into gametes. These unique gametes (like sperm) will be combined with other unique gametes (like eggs) to make a unique DNA template in the offspring.