CFCs are safe on Earth's surface but become very destructive to ozone when exposed to UV light in the upper ? Upper what

CFCs are broken down by UV photolysis, but the process takes a long time since it takes decades to cycle all of the air in the troposphere through the upper stratosphere. ... The photolysis of CFCs generates a highly reactive chlorine atom that can attack ozone or form compounds that destroy ozone. upper stratosphere should be your answer

answer; i believe the correct answer to the above question is ( friction)

answer-

the statement that f(x) = |x+a| + b has exactly one x-intercept is sometimes correct.

solution-

it solely depends on b, whether the function will have one or two or zero x intercept.

this plot of the given function, f(x) = |x+a| + b will be the basic absolute value graph i.e v shape, with vertex translated to (-a, b), instead of origin.

1-   if b is zero, the graph will have exactly one x-intercept, at x= -a

2- if b is positive, the whole graph will be above the x-axis, hence it will have no x-intercepts.

3- if b is negative, the graph will be below the x-axis, hence it will have two x-intercepts.

∴ the statement is sometimes true.