Question

select the correct answer. an interglacial is a period of time that occurs between ice - ages. its marked by warmer temperatures and milder climates. during previous interglacials, the co₂ levels in the atmosphere were about 200 parts per million (ppm). in 2013, they were approximately 400 ppm. rounding to the nearest percent, what is the percent increase in co₂ between these two time periods? a. 33% b. 70% c. 43% d. 240%

Explanation:

Step1: Identify the formula for percent - increase

Percent increase=$\frac{\text{New value}-\text{Old value}}{\text{Old value}}\times100\%$

Step2: Substitute the given values

The old value of CO₂ level is 280 ppm and the new value is 400 ppm.
Percent increase=$\frac{400 - 280}{280}\times100\%$
First, calculate the numerator: $400−280 = 120$
Then, $\frac{120}{280}\times100\%=\frac{12000}{280}\%$
$\frac{12000}{280}\approx42.86\%$
Rounding to the nearest percent, we get 43%.

Answer:

C. 43%