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

Polyblend is mixed with $\underline {i}$ and is used to lay $\underline {ii}$.

The World Summit on Sustainable Development $(2002)$ was held in which of the following countries?

Which of the following problems is not caused by noise pollution?

Human activities interfere with the carbon cycle. List any two such activities.

Consider the following statements about Ramesh Chandra Dagar's work in the field of organic farming:
$I.$ Ramesh Chandra Dagar's work includes bee-keeping,dairy management,water harvesting,composting,and agriculture in a chain of processes.
$II.$ In this process,there is no need to use chemical fertilisers for crops as cattle excreta is used as manure.
$III.$ Crop waste is used for making compost,which is used as natural fertilizer.
$IV.$ Compost generates natural gas,which is used for the energy needs of the farm.
Which of the statements given above are correct?