Answer:
Crossing over is the process of interchange of genetic information among non-sister chromatids of homologous chromosome pairs during meiosis (specifically during synapsis in prophase I). During this process, the synaptonemal complex enables the interchange of chromosome fragments between non-sister chromatids through crossing over. Moreover, in sexual reproduction, the zygote diploid cell can be generated by the random joining of fully differentiated haploid gametic cells (male and female gametes). The combination of random joining with the phenomenon of crossing over is known to considerably increase the genetic variation of the resulting offspring. After zygote formation, the successive cycles of cell divisions during embryonic development will develop an organism that during its adult stage will reproduce via sexual reproduction.