Presence of which gas in air makes respiration possible ?
Nitrogen
Hydrogen
Carbon dioxide
Oxygen
What do we need to breathe?
Inhaler
Smell
Vaporizer
Air
What is the process of purifying water by first boiling and then condensing called?
Sedimentation
Decantation
Distillation
Filtration
What percentage of the atmosphere consists of nitrogen?
68
76
78
88
The atmosphere is divided into:
5 layers
4 layers
3 layers
6 Layers
The amount of water vapour in the air is called:
Humidity
Evaporation
Condensation
Atmosphere
Which chemical is added to water to kill germs?
Chlorine
Ammonium
Arsenic
Benzene
Which layer of the atmosphere contains ozone gas?
Troposphere
Stratosphere
Mesosphere
Lithosphere
Which is the uppermost layer of the atmosphere?
Exosphere
Jet aircrafts fly in the :
