61.
The natural resource, known as black gold is

62.
The chief constituent of natural gas is:

63.
The resources which can be used continuously, year-after-year are called

64.
The highest volume of gases in lower atmosphere is comprised of

65.
What is the maximum Water Vapour content in the atmosphere?

66.
Which of the process is known as nitrification?

68.
Formation of ozone hole is maximum over

69.
Ozone saves the biosphere by absorbing high energy radiations called ________ .

70.
Which one of the following is not a cause for present global warming and climate change ?