മോണ്ട്രിയൽ ഉടമ്പടി ഒപ്പുവച്ച വർഷം ഏത് ?
A1987
B1997
C1992
D1981
A1987
B1997
C1992
D1981
Related Questions:
Which of the following statements are correct about atmospheric gases?
The composition of gases remains constant across all layers.
Oxygen becomes negligible at around 120 km altitude.
Hydrogen has the highest concentration among rare gases.