Ozone in the ___ is essential as it protects the Earth's surface from UV radiation, but ozone in the is a human-made air pollutant that contributes to global warming.
troposphere; stratosphere
stratosphere; troposphere
troposphere; thermosphere
mesosphere; stratosphere

stratosphere; troposphere

Explanation:

Ozone in the stratosphere is essential as it protects the Earth's surface from UV radiation, but ozone in the troposphere is a human-made air pollutant that contributes to global warming.

explanation: no but i do not usually comment

answer:

the answer is 6 valence electrons.

explanation:

valence is the # of electrons on the outer most shell of an atom.

oxygen has 6.

although, the valency of oxygen is 2, because it only needs to make 2 covalent bonds, or gain 2 electrons, to achieve the stable octet configuration of a noble gas.

that's it!

if you need further assistance, let me know: )

~ trueboss72