What retains heat and block out the harmful rays of the sun?
earth
wind
weather
atmosphere
Which is the third layer of the atmosphere?
Troposphere
Stratosphere
Mesosphere
Exosphere
When do we say the air has low humidity?
wet
dry
cloudy
dust
Which is the second layer of the atmosphere?
During which process, the heavier impurities will settle down at the bottom of the beaker?
sedimentation
decantation
filtration
distillation
What crystals are added in well to purify water?
copper sulphate
potassium permanganate
sodium hydroxide
potassium dichromate
After sedimentation, drain the clear water carefully into another beaker .It is called:
condensation
What is formed because of the evaporation of water from the surface of water bodies like seas, rivers and lakes?
hydrogen
water vapour
argon
helium
What do plants get with the help of bacteria in the soil?
oxygen
nitrogen
carbonmonoxide
What do we call the fresh air that we breath?
inhaled
exhaled
expired
burned
