What is needed for cooking, bathing, working and construction work?
water
food
light
cloth
As we go up a mountain, air pressure:
decreases
increases
constant
is not there
Which gas is added to water to kill bacteria?
hydrogen
chlorine
nitrogen
bromine
What is the process of separation of a mixture of soil from water by using filterpaper called?
sedimentation
decantation
distillation
filtration
Which is the fifth layer of the atmosphere?
exosphere
thermosphere
troposphere
stratosphere
The amount of water vapour present in the air is called:
humidity
viscosity
fluidity
density
What is taken from the inhaled air by the blood in our lungs?
oxygen
carbondioxide
What is the process of purification of a liquid by changing it into vapour by heating and then condensing it into a pure liquid called?
evaporation
condensation
What is used to produce the colourful glow in glass tubes?
argon
helium
carbonmonoxide
Which of the following present in air is needed for burning?
