The surface of the earth has _____ of its total area as land
Two thirds
One thirds
Two fifths
One tenths
When hydrogen and oxygen combine to form water, they form
An unstable compound
A stable mixture
An unstable mixture
An extremely stable compound
The density of water is
0.1 g/cm3
1 g/cm3
100 g/cm3
1 kg/m3
Which of the following statement is true ?
The salinity of rivers increase with time
The salinity of rivers decrease with time
The salinity of seas increase with time
The salinity of seas decrease with time
Which of the following is potable water
A glass of water fit for drinking
Water in a pot
Sea water
Water with bacteria and chemicals
The main source of water for perennial rivers is in the form of
Lakes
Rain water
Snow
Dams
The process of obtaining salt from sea water involves
Evaporation
Condensation
Sublimation
None
The main source of water for inland lakes are:
Ground water
None of these
What happens to the water table of a place having droughts for a long period of time ?
It gets higher because of continuous evaporation
It gets lower because of continuous evaporation and flow
It remains the same because soil protects it from the heat
It gets replenished continuously
Which of the following processes cannot take place in the absence of oxygen ?
Combustion
Respiration
Oxidation
All of these