Question : How much percentage of nitrogen is present in the atmosphere?

Option 1: 78%

Option 2: 89%

Option 3: 67%

Option 4: 71%

Question : The percentage of nitrogen present in ammonium sulphate is:

Option 1: 21%

Option 2: 25%

Option 3: 30.5%

Option 4: 18%

Question : Simplify the following expression.
$\frac{7}{10} \div \frac{3}{7}$ of $\left(2 \frac{3}{10}+2 \frac{3}{5}\right)+\frac{1}{5} \div 1 \frac{2}{5}-\frac{2}{7}$

Option 1: $-\frac{4}{21}$

Option 2: $\frac{5}{21}$

Option 3: $\frac{4}{21}$

Option 4: $-\frac{5}{21}$

Question : What is the correct percentage by volume of various gases in Earth's atmosphere?

Option 1: 20.95% nitrogen, 78.09% oxygen and 0.04% carbon dioxide and other greenhouse gases

Option 2: 10.95% nitrogen, 88.09% oxygen and 0.09% carbon dioxide and other greenhouse gases

Option 3: 10.95% nitrogen, 78.09% oxygen and 0.03% carbon dioxide and other greenhouse gases

Option 4: 78% nitrogen, 21% oxygen and 0.03% carbon dioxide and other greenhouse gases

Question : Oxygen liberated during photosynthesis comes from:

Option 1: Carbon dioxide

Option 2: Water

Option 3: Breakdown of chlorophyll

Option 4: Atmosphere