How does crossing over add to the genetic diversity of sexually reproducing organisms?
it involves segments of two homologous chromosomes trading places.
it involves random segregation of the homologous chromosomes to each daughter cell.
it involves fertilization of an ovum by any one out of millions of sperms.

It involves segments of two homologous chromosomes trading places.

Explanation:

Crossing over is the process of exchange of genetic segments between two non-sister chromatids of a homologous chromosome pair. It occurs in pachytene of prophase I of meiosis I. The exchange of segments between non sister chromatids of a homologous chromosome pair creates new gene combinations. So, crossing over creates genetic diversity by adding new gene combinations to gametes.

step 1: nitrogen fixation- conversion of atmospheric no₂ into forms useful to plants by lightning, bacteria, and cyanobacteria.

step 2: nitrification-process of converting ammonia to nitrite or nitrate.

step 3: assimilation-plant roots absorb new form of nitrogen.

step 4: ammonification-conversion of organic nitrogen to ammonia by bacteria involved in decomposition.

step 5: denitrification-bacteria turns the decomposed matter back into n₂o, which is released into atmosphere; repeat cycle.

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