Crossing over, true is;
Crossing over is the exchange of genetic material between non sister chromatids of homologous chromosomes occuring during pachytene stage of prophase I of meiosis.Recombination of genes in the same chromosome is brought about by crossing over. Ref: PRINCIPLES OF GENETICS, By Eldon John Gardner, Michael J. Simmons, D. Peter Snustad, 8th Edition, Page 163