What impact do plants have on your daily life?

How many electrons can occupy any electron orbital?

Steven hawking is on record as saying that viruses can be considered a form of life. considering the list above, what might be his evidence? a) item 5 b) items 1 - 3 c) items 4 - 7 d) items 1 & 2

Waste water from industries and domestic sources can be treated by chlorination or ultraviolet radiation. there are pros and cons to using either chlorine or uv radiation to kill harmful microorganisms. what is one reason chlorination would be preferred over ultraviolet radiation? a) chlorine only eliminates visible impurities and is ineffective against microorganisms. b) chlorine not only kills bacteria but provides a residual effect on returning microorganisms. c) uv radiation can be used only to treat drinking water and is ineffective in treating waste water. d) ultraviolet radiation is more effective