Answer:
When homologous chromosomes form pairs during prophase I of meiosis I, crossing-over can occur. Crossing-over is the exchange of genetic material between homologous chromosomes. It results in new combinations of genes on each chromosome. It is obviously another source of genetic variation in offspring.
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Because we have been to busy trying to explore new areas rather than our own and were probably to scared to know what's in our planet so it doesn't cause panic
