Which sentences in this excerpt from jack london's "the human drift" express the main argument of the excerpt? it has always been so, from the time of the first pre-human anthropoid crossing a mountain-divide in quest of better berry-bushes beyond, down to the latest slovak, arriving on our shores to-day, to go to work in the coal-mines of pennsylvania. these migratory movements of peoples have been called drifts, and the word is apposite. unplanned, blind, automatic, spurred on by the pain of hunger, man has literally drifted his way around the planet. there have been drifts in the past, innumerable and forgotten, and so remote that no records have been left, or composed of such low-typed humans or pre-humans that they made no scratchings on stone or bone and left no monuments to show that they had been. these early drifts we conjecture and know must have occurred, just as we know that the first upright-walking brutes were descended from some kin of the quadrumana through having developed "a pair of great toes out of two opposable thumbs." dominated by fear, and by their very fear accelerating their development, these early ancestors of ours, suffering hunger-pangs very like the ones we experience to-day, drifted on, hunting and being hunted, eating and being eaten, wandering through thousand-year-long odysseys of screaming primordial savagery, until they left their skeletons in glacial gravels, some of them, and their bone-scratchings in cave-men's lairs. there have been drifts from east to west and west to east, from north to south and back again, drifts that have criss-crossed one another, and drifts colliding and recoiling and caroming off in new directions. from central europe the aryans have drifted into asia, and from central asia the turanians have drifted across europe.