Terracing is done in

Choose the correct option regarding the following statements:
$(1)$ $CO_2$ contribution in global warming is $60\%$.
$(2)$ Greenhouse effect occurs due to deforestation.
$(3)$ Due to the greenhouse effect,the present average temperature at the surface of the Earth is $15^oC$.
$(4)$ The amount of $DDT$ in small fish is $0.05\ ppm$.

Jhum cultivation is prevalent in $.................$.

Where was the $UN$ Climate Change Conference held in $2012$?

Which of the following is $NOT$ true regarding the Bhopal Gas Tragedy?

What do '$X$','$Y$',and '$Z$' represent in the given figure respectively?