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 $0.05\ ppm$.

Describe the integrated wastewater treatment project in the town of Arcata,California.

Burning of fossil fuels affects which of the following cycles?

Select the correct option for 'Ecosan'.

Ruthless exploitation and pollution of the environment has increased the magnitude of waste materials,which has disturbed the operations of all important:

Which of the following statements is/are correct?
$I.$ Chemical fertilizers cause pollution of water bodies as well as groundwater,besides getting stored in crop plants. Therefore,environmental scientists are pressing for a switch over to organic farming.
$II.$ Organic farming is a form of agriculture that relies on techniques such as crop rotation,green manure,compost,and biological pest control.