What is the primary outcome of crossing over during prophase of meiosis I?

Chromosomes duplicate without any exchange of parts

Homologous chromosomes exchange different pairs leading to recombinant chromatids and increased genetic variation

Homologous chromosomes exchange identical parts resulting in no genetic variation

Non-homologous chromosomes exchange part

During crossing over in meiosis I, homologous chromosomes exchange different segments, leading to genetic recombination and increased variation.