Which of these protects the Earth from harmful radiation when found in the stratosphere, but is a pollutant at lower altitudes? A. carbon B. oxygen C. ozone D. hydrogen

Carbon

Explanation:

if he does not use open the compass the a width greater than half of po, he will not be able to find the midpoint of the line, without the midpoint of the line, he will not be able to bisect the line.   to find the midpoint of a line the circles drawn with a compass must either intersect or be touching.