Question

how does crossing over contribute to genetic diversity? crossing over adds entirely new genes to chromosomes to allow for new genetic outcomes, allowing for more genetic combinations. crossing over puts the chromosomes received from each parent together to make new traits, allowing for more genetic combinations. crossing over deletes old genes from chromosomes, allowing for more genetic combinations. crossing over trades genes to create unique chromosomes that are different from parent chromosomes, allowing for

Explanation:

Crossing over occurs during meiosis. Homologous chromosomes pair up and exchange segments of genetic material. This is not about adding entirely new genes (as in the first option, new genes would come from mutations mainly), nor is it about just putting chromosomes from each parent together (the second option is too simplistic as it's about gene - segment exchange, not whole - chromosome combination in that sense), and it's not about deleting old genes (third option). It's about trading gene segments (recombination) between homologous chromosomes. This recombination creates new combinations of alleles on chromosomes, which are different from the parental chromosomes.

Answer:

Crossing over trades genes to create unique chromosomes that are different from parent chromosomes, allowing for more genetic combinations.