Question $41$: $[1]$ The chart at right illustrates the fluctuation in Earth$$s atmospheric CO$2$ seasonally in ppm over two years. Measurements are from the Mauna Loa Observatory$4$ via the Scripps Institution of Oceanography. The curve of daily CO$2$ values is called the Keeling Curve.

If the maximum observed in a year

was $421$ ppm and the minimum was $417$ ppm then the seasonal variation over the year is $4$ ppm$.$

What is the $4$ ppm variation expressed as a percentage of the base value $($lowest value$)$ measured of $417$ ppm$?$

$($keep $2$ decimal places in your answer$)$

$($E$.$g$.,$ if you got $15$ out of $408$ on a test you would have gotten $3\mathrm{.}68\%,$ it is the same math$)$

Question $42$: $[1]$ At right is the data of CO$2$ in ppm for Earth$$s atmosphere over the past $60$ years or so$,$ something you have probably heard or read about. If the lowest observed is $314$ ppm $($in $1958)$ and the maximum is $423$ ppm $($May $2023)$ then the total spread is $109$ ppm$.$

What is the $109$ ppm change expressed as a percentage of the $314$ ppm lowest annual peak $($base value$)$ measured?

$($keep $2$ decimal places in your answer$)$