<span>b. nitrogen is your answer :)</span>
<span>The precambrian period was a time period that happened billions of years ago. Actually, 4.6 billion years, to be exact. The Earth started to form during this period. Layers of rock, elements of the land and waters, and many other things were developed during this time. The atmosphere had a mind of its own, per se, during this time period. It went through many different changes. The atmosphere went from being extremely cold and galactic to warming and having volcanoes, which allowed for an expansion of life forms.</span>
<span>Radiometric dating such as carbon 14, Uranium 238, 235, and 234, Thorium 232, Rubidium 87, and Potassium 40. This is not an exhaustive list. Each of these different isotopes have a different half life, so they can be used to measure different ages, from million to billions of years.</span>
Under Communist leadership, North Korea has continued to evolve into a capitalist country. All deals that they make outside the country is leading towards capitalism and gaining an upper hand. This country has recently exposed a powerful nuclear missile and has shown the world their capabilities.
