Why does one species include animals that are very different from each other, such as a great dane, a lapdog, a dachshund, a greyhound, and similar species, such as a house mouse and a field mouse, to different species?
because a great dane, a lapdog, etc. are breeds of the same species artificially isolated by a man, and a house mouse and a field mouse are different species that arose in nature. All dog breeds have the same number of chromosomes and can cross, and different types of mice are different
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