In the stratosphere, which of the following element acts as a catalyst in the degradation of ozone and release of molecular oxygen?

1. Carbon
2. Cl
3. Fe
4. Oxygen

Which of the following is a secondary pollutant?

$1.$ $\mathrm{CO}$

$2.$ ${\mathrm{CO}}_2$

$3.$ ${\mathrm{SO}}_2$

$4.$ ${\mathrm{O}}_3$

Match the items given in Column I with those in Column II and select the correct option given below: 

Rachel Carson's famous book 'Silent Spring' is related to:

Which of the following is not one of the prime health risks associated with greater UV radiation through the atmosphere due to the depletion of the stratospheric zone?

Which one of the following pairs of gases are the cause of 'Greenhouse effect'?

1. ${\mathrm{CO}}_2$ $\mathrm{and}$ $\mathrm{CO}$

2. ${\mathrm{CFC}}_{\mathrm{s}}$ $\mathrm{and}$ ${\mathrm{SO}}_2$

3. ${\mathrm{CO}}_2$ $\mathrm{and}$ ${\mathrm{N}}_2\mathrm{O}$

4. ${\mathrm{CO}}_2$ $\mathrm{and}$ ${\mathrm{O}}_3$