Identify the property of air.

• Air has weight

• Air exerts pressure

• Air occupies space

• Air is transparent

In which of the following processes is oxygen used up?

1. burning

2. photosynthesis

3. respiration

• Only (i) and (2)

• Only (2) and (3)

• Only (1) and (3)

• 1, 2 and 3

Which of these protects us from the harmful rays of the sun?

• Ionosphere

• Ozone

• Strartosphere

• Hydrosphere

Which component of air cannot be used directly by the living beings?

• Oxygen

• Nitrogen

• Carbon dioxide

• Water vapour

The process in which impure dirty water is allowed to stand undisturbed in a container is called _________.

• Filtration

• Sedimentation

• Decantation

• Evaporation

The easiest and most common method to purify water before consumption is ____________.

Things like syringe, dropper,drinking straw work on the principle of _________________.

• Water pressure

• Air pressure

• Pressure of container

• All of these

Which among the following are true about air?

• We cannot feel air

• We cannot see air

• We cannot smell air

• We cannot taste air

After sedimentation, the action of pouring clear water out into another container is called __________.

• distillation

• decantation

• filtration

• chlorination

Air is a mixture of_________.