Amount of carbon fixed annually through photosynthesis is
4.6 Χ 1010 kg
7 Χ 1013 kg
7 Χ 1020 kg
4.6 Χ 1021 kg
The reason for green house effect is
Higher CO2 concentration causing global warming
Absorption of infra-red rays by gases and dust particles
Both A and B
Refraction of CO2
Process of evapo-transpiration and precipitation is called
Carbon cycle
Nitrogen cycle
Hydrological cycle
All the above
Climate of the world is threatened by
Increasing concentration of atmospheric oxygen
Decreasing concentration of atmospheric oxygen
Increasing amount of atmospheric carbon dioxide
Decreasing amount of atmospheric carbon dioxide
In one year, one hectare of forest shall
Consume 10 tonnes of CO2 and evolve 10 tonnes of O2
Consume 20 tonnes of CO2 and evolve 10 tonnes of O2
Consume 30 tonnes of CO2 and evolve 30 tonnes of O2
The combustion of fossil fuels and deforestation have caused the atmospheric concentration of carbon dioxide to increase by about 35% since the beginning of the age of industrialization. Hence consumption of carbon dioxide will increase every year.
A green house gas is
H2
CO
CO2
N2
Green-house gases are
Absorbers of long-wave radiations from earth
Transparent to both solar radiations and long-wave radiations from earth
Absorbers of solar radiations for warming the atmosphere of earth
Transparent to emissions from earth for passage into outer space
Ozone layer is found in
Thermosphere
Stratosphere
Lithosphere
Mesosphere
Earth is an
Open system
Closed system
Both open and closed system
Neither A and B
Biogeochemical cycles are also known as
Sedimentary cycles
Gaseous cycles
Material cycling
Cyycles of water
