Which diagram demonstrates how crossing-over contributes to genetic variety during meiosis?

Me with these questions if you’re it sure don’t answer

The bacteria found in soil is usually harmful and measures are taken to remove any traces of microorganisms. true or false

Agene pool: a) is the collection of all the alleles found in a single species b) is the collection of all the alleles found in a single population c) is the collection of all the chromosomes found in a single population d) is the collection of genes in a species that allow the individuals to swim