<span>The stage at which all the cells show crossover chromosomes is meiotic prophase I. The crossover is the exchange of genetic material between homologous chromosomes. Homologous chromosomes are present in the meiosis I. Regarding the phase of meiosis I, it is expected that the crossover takes place in meiotic prophase I since homologous chromosomes pair up in the prophase.</span>
This has something to do with winter seasons. You see, during winter days, <span>the sun is further down in the sky, so the same circle of sunlight covers a wider area, so there is less light per plant. In this case, those plants that are pointing straight at the sun have higher chances of growing better. Hope this answers your question.</span>