During Prophase I, which is the first division stage of meiosis I, homologous chromosomes pair up with each chromosome aligning with its homologue partner to form a TETRAD structure. At this stage, segments of each homologous chromosome break and get refixed interchangeably i.e trade parts. This process is called Crossing-over or RECOMBINATION
Crossing-over is the process whereby two chromosomes of a homologous pair (non-sister chromatids) exchange equal segments with each other to form two recombinant chromosomes.
Crossing-over accounts for genetic variation due to the swapping of genetic material. Some of the daughter cells receive daughter chromosomes with recombined alleles. Due to this genetic recombination, the offspring have a different set of alleles and genes than their parents do.
Gases move from high-pressure areas to low-pressure areas. The bigger the difference between the pressures, the faster the air will move from the high to the low pressure.
