Scientists Explain Why Can Pet Dander Make You Sick Now

The (i)_____________scientists-the notion that they are elitists scornful of the masses is in no sense (ii)_____________the eighteenth century, since in our own time one does not have to look far to find. The two scientists' achievements are _____________ only in a narrowly conceived history of science: although both erred in scientific judgment, both also defended science in its infancy and established. Scientists could not build on each other's work if they could not trust the published work of their colleagues; thus progress in science depends on the ____________ of practicing scientists. Scientists have long debated the exact timing of the lunar cataclysm, a period approximately 4 billion years ago when Earth and the Moon were pummeled with asteroids. A clue to this puzzle may come.