They can estimate how old the universe is by testing rocks from different planets and comparing ages and comparing with our earth so since we know approximately how old are earth is we can tell how old the universe is
Ever since the discovery of the Neanderthal fossils, expert opinion has been divided as to whether Neanderthals should be considered a separate species (Homo neanderthalensis) or a subspecies (Homo sapiens neanderthalensis) relative to modern humans.
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