Approximately what fraction of the atmosphere is composed of oxygen? Looking at the data again, the atmosphere is approximately 78% Nitrogen, 21% Oxygen and 1% other gases. 1/2 1/5 1/4 1/3

The correct answer is $1/5$.<br /><br />Explanation:<br />According to the data provided, the atmosphere is composed of approximately 21% oxygen. To express this as a fraction, we can divide 21 by 100, which gives us $21/100$. Simplifying this fraction, we get $1/5$. Therefore, the fraction of the atmosphere composed of oxygen is approximately $1/5$.