The maximum biomagnification would be in which of the following in case of an aquatic ecosystem?

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 $0.05\ ppm$.

Write critical notes on the following:
$(a)$ Eutrophication
$(b)$ Biomagnification
$(c)$ Groundwater depletion and ways for its replenishment

Match the Column-$I$ with Column-$II$:

Column-$I$	Column-$II$
$(a)$. Pyrolysis	$(i)$. Methaemoglobinemia
$(b)$. Carbon monoxide	$(ii)$. Chronic exposure to arsenic
$(c)$. Blue baby syndrome	$(iii)$. Asphyxia and giddiness
$(d)$. Black foot disease	$(iv)$. Disposal of hospital waste

For plastic waste,ragpickers used to get $P$ rupees per kilogram. Now,because of Ahmed Khan,they have started receiving $Q$ rupees per kilogram.

Where are Ecosan toilets used?