(1) What is nitrogen cycle?
(2) What is ozone layer? What is the significance of it?
(3) How is the water returning to water bodies?
(4) Can we reverse the soil erosion?
(5) What are the natural resources?
(6) How to control air pollution?
(7) What is the humus?
(8) What is the global warming and its consequences?
(9) Why carbon cycle is necessary?
(10) What will be the direction of air which would flow at night in coastal areas?