How many elements are there in period 4?

A) 2
B) 6
C) 8
D) 18


D

Environmental & Atmospheric Sciences

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What circumstance would decrease the likelihood of a couple having a child?

A. the use of children as an essential part of the family labor force B. lack of contraceptive availability C. opportunities for women to participate in education and employment D. the lack of a public or private pension system E. high infant mortality rates

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The light inside a raindrop that emerges into the air

A. speeds up. B. slows down. C. remains at speed c. D. none of the above

Environmental & Atmospheric Sciences

If you have one molecule of TiO2, how many molecules of O2 does it contain?

A. Three, TiO2 contains three molecules. B. Two, TiO2 is a mixture of Ti and 2 O. C. One, TiO2 is a mixture of Ti and O2. D. None, O2 is a different molecule than TiO2. E. none of the above

Environmental & Atmospheric Sciences

Discharge permits and the Clean Air Act and Clean Water Act

A) do not allow any wastes to be dumped into natural waterways. B) limit the type but not the amount of wastes dumped into natural waterways. C) limit the amount but not the type of wastes dumped into natural waterways. D) limit the type and the amount of wastes dumped into natural waterways.

Environmental & Atmospheric Sciences