Answer:
The correct answer is methane . Nature constitutes most of the substances made up of organic compounds. These compounds have carbon atoms attached with hydrogen atoms with a chemical bond (very few compounds may not have this bond).
<span>As humans change the way we live on the planet, the way that nitrogen moves around the Earth also changes. Nitrogen atoms may seem small enough to be easily overlooked. We look right through the ones in the air, do we not? Yet recent changes in the nitrogen cycle are causing a very noticeable effect on natural environments and human health. Lakes are clogged with aquatic weeds. Dead zones have formed in areas of the oceans where animals can not survive. Air pollutants that contain nitrogen are decreasing air quality and greenhouse gases that contain nitrogen are becoming more common.</span>
Mendeleev called the rows periods.
