Phase Inspection. 1  Framing: proper technique, boring & notching, wood grade, defective or missing members. 2  Window and door installation and water proofing. 3  Exterior sheathing and vapor barrier is correctly installed. â 4 Plumbing and Electrical inside the walls with correct nail stop shield placement.
Hydrogen is the lightest of the elements and is the most abundant element in the universe. (Also reference http://www.ducksters.com/science/chemistry/hydrogen.php) earth's atmosphere
The Earth's atmosphere has remained much the same for the past 200 million years. The pie chart shows the proportions of the main gases in the atmosphere. It is clear that the main gas is nitrogen. Oxygen - the gas that allows animals and plants to respire, and fuels to burn - is the next most abundant gas. These two gases are both elements and account for about 99% of the gases in the atmosphere.