The answer is the second one
When silicon atoms bond, then silicates form which are minerals in which such elements as potassium, calcium, magnesium and aluminum combine with the silicon atoms to form minerals like feldspars of different types or if it is just silicon and oxygen that bond then it forms quartz.
For humans, population density is the number of people per unit of area, usually quoted per square kilometer or square mile (which may include or exclude, for example, areas of water or glaciers). Commonly this may be calculated for a county, city, country, another territory or the entire world.
Answer:
Proper cleanliness of water..
The Gulf Steam
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