Sentences with phrase «definite span of years»
Since these elements exist only for a definite span of years, and all the uranium, radium, thorium and other radioactive elements in the world today have not yet existed that many years, there was a time, prior to the duration of this span in the past, when these elements DID NOT EXIST!
http://religion.blogs.cnn.com/ Not exact matches
It shows a definite increase in the emission of carbon in the last 200 years of a 1000 year time span from fossil fuel burning by humans in the northern hemisphere.