Air pollution. Cleaner burning than other fossil fuels, the combustion of natural gas<span> produces negligible amounts of sulfur, mercury, and particulates. Burning</span>natural gas does<span> produce nitrogen oxides (NOx), which are precursors to smog, but at lower levels than gasoline and diesel used for motor vehicles.</span>
The level of organization is plants, coral and water. Water came first.
HCL is guilty for triggering the release of enzymes such as pepsin which are essential for the digestion of protein. Bile contains bile acids, which are critical for digestion and absorption of fats and fat-soluble vitamins in the small intestine.
the answer is b) shoppers no longer need to leave the house or spend hours at the mall to make a purchase