Q.Explain how independent assortment of homologous chromosome pairs during meiosis I contributes to genetic variation among the gametes produced.

[!TLDR]

Each bivalent orients at metaphase I independently, so the mix of maternal/paternal chromosomes in each gamete is randomised, producing many possible combinations. …

At metaphase I, each bivalent -- a pair of homologous chromosomes, one originally inherited from each parent -- becomes aligned at the equatorial plate independently of how every other bivalent is aligned. Consequently, when the members of each bivalent separate at anaphase I, which pole receives the maternal chromosome and which receives the paternal chromosome of that particular pair is essentially a matter of chance, and this chance orientation is independent from one chromosome pair to the next. With many chromosome pairs assorting independently in this way, the number of distinct combinations of maternal and paternal chromosomes that can end up together in a single haploid gamete becomes extremely large, so that an individual's gametes -- and hence its potential offspring -- can differ enormously in their genetic make-up from one another, contributi …

Focus on the word 'independent' -- each bivalent's orientation at metaphase I does not depend on any other bivalent's orient …

Confusing independent assortment (random orientation of DIFFERENT chromosome pairs relative to each other) with crossing over (exchange of material WITHIN a sing …