Answer:
<em> A. 38%</em>
Explanation:
Percentage increase in carbon dioxide concentration = (Increase in concentration of carbon dioxide/initial concentration)×100
P = (C₂-C₁/C₁)×100...................... Equation 1
Where P = percentage increase in the concentration of carbon dioxide from 1970 to 2007, C₁ = The atmospheric concentration of carbon dioxide in 1970, C₂ = The atmospheric concentration of carbon dioxide in 2007.
<em>Given: C₁ = 278 ppm, C₂ = 383 ppm.</em>
Substituting these values into equation 1
<em>P = [(383-278)/278]×100</em>
<em> P = (105/278)×100</em>
<em>P = 37.7%</em>
<em>P ≈ 38%</em>
<em>Thus the approximate percentage increase in carbon dioxide concentration from 1790 to 2007 is 38%</em>
<em>The right option is A. 38%</em>
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