………… is essential for plants.
a) CO2
b) SO2
c) O3
d) CO
Nitrogen is useful macro nutrient for………
a) animals
b) plants
c) both a & b
d) none of these
The amount of…………in the atmosphere goes on changing and directly effects the living beings.
a) carbon
b) oxygen
c) water vapours
d) nitrogen
…………protect all kinds of life on the earth from the harmful UV rays of the Sun.
a) Ozone
b) animals
c) plants
d) all of these
……maintain the heat balance by absorbing the heat radiation reemitted by earth.
a) atmosphere
b) mesophere
c) tropsphere
d) thermosphere
Atmosphere prevents excessive heating of surface of the earth at day and excessive cooling at night thereby reducing the……… variations.
a) pressure
b) temperature
c) volume
d) density
