As a result of which treaty, ozone hole in Antarctica is slowly healing
How many meters are in one mile
Montreal Protocol 1987 was__________
Disolved oxygen (DO) in water should be
Why normal rain is slightly acidic
The yellow colour in photochemical smog is due to the presence of____________
Human beings use _______ liters of pure oxygen per day
In 2013, Planck measured the age of the universe at ___________
Jupiter has ________ known moons
When a single month has two full moons, the second moon is called________
