Which of the following pairs of gases is mainly responsible for the greenhouse effect?

If there were no greenhouse effect on Earth,the average temperature of the Earth's surface would have been $.....P.....$ instead of $.....Q.....$.

What are the correct proportions of the two gases responsible for the greenhouse effect?

The major factor in causing global warming is

Consider the following statements and select the correct set with respect to global warming:
$(a)$ $El$ $Nino$ effect
$(b)$ Cooling of stratosphere and earth surface
$(c)$ Shifting of climatic zones
$(d)$ Snow blindness
$(e)$ Impairment of hearing
$(f)$ Excessive deposition of ice at poles
$(g)$ Rise in sea level
$(h)$ Increase in eutrophication

Select the appropriate option regarding the El Niño effect.