The mechanism is straightforward: in Metaphase one of Meiosis, chromosomes line up in two lines, with homologous across from each other, which allows them to interact by crossing over. In Metaphase of Mitosis, the chromosomes are all lined up single file, so the homologous chromosomes cannot interact.
I think to get more oxygen for the lungs. Hope this helped.
Air travel is usually the largest component of the carbon footprint of frequent flyers. A single return flight from London to New York – including the complicated effects on the high atmosphere – contributes to almost a quarter of the average person’s annual emissions. The easiest way to make a big difference is to go by train or not take as many flights.
2 The second most important lifestyle change is to eat less meat, with particular emphasis on meals containing beef and lamb. Cows and sheep emit large quantities of methane, a powerful global warming gas. A vegan diet might make as much as a 20% difference to your overall carbon impact but simply cutting out beef will deliver a significant benefit on its own.