What is the nitrogen cycle?

The nitrogen cycle is the process by which nitrogen in the atmosphere is converted into forms usable by living organisms. Steps: (1) Nitrogen fixation — N₂ gas converted to ammonia by Rhizobium bacteria (in legume roots) or by lightning; (2) Nitrification — ammonia converted to nitrites and nitrates by nitrifying bacteria; (3) Assimilation — plants absorb nitrates, animals eat plants; (4) Denitrification — denitrifying bacteria convert nitrates back to N₂ gas.

What is the difference between renewable and non-renewable resources?

Renewable resources can be replenished naturally at a rate comparable to human use — examples include sunlight, wind, water, forests. Non-renewable resources take millions of years to form and are used up much faster than they are created — examples include coal, petroleum, and natural gas (fossil fuels). Conservation of non-renewable resources is critical because once depleted, they cannot be replaced.

What is the ozone layer and why is it important?

The ozone layer is a region in the stratosphere (15–35 km above Earth) that contains high concentrations of ozone (O₃). It absorbs harmful ultraviolet (UV) radiation from the Sun. Without the ozone layer, UV radiation would cause skin cancer, cataracts, and damage to plants and marine ecosystems. It is depleted by CFCs (chlorofluorocarbons) used in refrigerants and aerosols.

Conservation of Natural Resources

Natural Resources • Class 9 Science • NCERT • CBSE

Natural resources include air, water, soil, forests, wildlife, and minerals. They must be conserved because they are limited. The water cycle, carbon cycle, nitrogen cycle, and oxygen cycle are the major biogeochemical cycles that maintain balance in nature.

Frequently Asked Questions

What is the nitrogen cycle?: The nitrogen cycle is the process by which nitrogen in the atmosphere is converted into forms usable by living organisms. Steps: (1) Nitrogen fixation — N₂ gas converted to ammonia by Rhizobium bacteria (in legume roots) or by lightning; (2) Nitrification — ammonia converted to nitrites and nitrates by nitrifying bacteria; (3) Assimilation — plants absorb nitrates, animals eat plants; (4) Denitrification — denitrifying bacteria convert nitrates back to N₂ gas.
What is the difference between renewable and non-renewable resources?: Renewable resources can be replenished naturally at a rate comparable to human use — examples include sunlight, wind, water, forests. Non-renewable resources take millions of years to form and are used up much faster than they are created — examples include coal, petroleum, and natural gas (fossil fuels). Conservation of non-renewable resources is critical because once depleted, they cannot be replaced.
What is the ozone layer and why is it important?: The ozone layer is a region in the stratosphere (15–35 km above Earth) that contains high concentrations of ozone (O₃). It absorbs harmful ultraviolet (UV) radiation from the Sun. Without the ozone layer, UV radiation would cause skin cancer, cataracts, and damage to plants and marine ecosystems. It is depleted by CFCs (chlorofluorocarbons) used in refrigerants and aerosols.

Study With GyanAI

GyanAI's AI tutor can answer any question about this topic instantly. Try GyanAI free for step-by-step NCERT solutions aligned with the CBSE curriculum.