Darwin's observations on the Galapagos islands led him to question the fixity of species rather than to the discovery of the mechanism of natural selection.
(Darwin's observations on the Galapagos islands; led; him; to question the fixity of species rather than to the discovery of the mechanism of natural selection) (him; to question; the fixity of species rather than to the discovery of the mechanism of natural selection)
Darwin's observations on the Galapagos islands him
led to question
him to question the fixity of species rather than to the discovery of the mechanism of natural selection
the fixity of species rather than to the discovery of the mechanism of natural selection