Assertion (A): The ozone layer plays a critical role in
protecting life on Earth.
Reason (R): The ozone layer absorbs most of the harmful
ultraviolet radiation from the Sun.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The ozone layer absorbs UV radiation, protecting
living organisms from harmful effects such as skin cancer and cataracts.
Assertion (A): Chlorofluorocarbons (CFCs) are responsible for
the depletion of the ozone layer.
Reason (R): CFCs release chlorine atoms that break down ozone
molecules in the stratosphere.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: CFCs release chlorine atoms, which catalytically
destroy ozone molecules, leading to ozone layer depletion.
Assertion (A): The green revolution has led to the
contamination of groundwater.
Reason (R): The extensive use of chemical fertilizers and
pesticides in the green revolution has caused leaching into water bodies.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The use of chemical fertilizers and pesticides
during the green revolution has led to groundwater contamination due to the
leaching of chemicals into the soil and water.
Assertion (A): Global warming is a significant environmental
issue.
Reason (R): The burning of fossil fuels increases the
concentration of greenhouse gases in the atmosphere, leading to global warming.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The burning of fossil fuels releases CO2 and other
greenhouse gases, which trap heat in the atmosphere and contribute to global
warming.
Assertion (A): Deforestation leads to loss of biodiversity.
Reason (R): Deforestation causes habitat destruction, which
threatens plant and animal species.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Deforestation leads to the destruction of
habitats, which reduces biodiversity and threatens the survival of species.
Assertion (A): Acid rain is caused by the emission of sulfur
dioxide and nitrogen oxides.
Reason (R): These gases react with water vapor in the
atmosphere to form sulfuric and nitric acid.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Sulfur dioxide and nitrogen oxides react with
water vapor to form sulfuric acid and nitric acid, resulting in acid rain.
Assertion (A): Eutrophication leads to the depletion of oxygen
in water bodies.
Reason (R): The excessive nutrient load leads to the growth of
algae, which consumes oxygen as it decomposes.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Eutrophication causes algae blooms, which consume
oxygen during decomposition, leading to oxygen depletion in water.
Assertion (A): Biodegradable wastes cause lesser environmental
harm than non-biodegradable wastes.
Reason (R): Biodegradable wastes can be broken down by
microorganisms into harmless substances.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Biodegradable wastes decompose naturally through
microbial action, causing minimal environmental harm compared to
non-biodegradable wastes, which persist in the environment.
Assertion (A): Ozone depletion contributes to skin cancer.
Reason (R): Ozone depletion allows higher levels of ultraviolet
radiation to reach the Earth's surface.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Depletion of the ozone layer leads to an increase
in UV radiation, which can cause skin cancer.
Assertion (A): The use of renewable energy sources can reduce
environmental pollution.
Reason (R): Renewable energy sources like wind and solar power
do not release harmful pollutants into the atmosphere.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Renewable energy sources like solar, wind, and
hydropower are clean and do not emit pollutants, reducing environmental
pollution.
Assertion (A): The greenhouse effect is essential for
maintaining life on Earth.
Reason (R): The greenhouse effect helps in retaining heat from
the Sun, keeping the Earth warm enough to support life.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The greenhouse effect is crucial for life, as it
traps heat from the Sun, maintaining a temperature that supports life on Earth.
Assertion (A): Overuse of water resources leads to water
scarcity.
Reason (R): Excessive withdrawal of groundwater and surface
water faster than they can be replenished results in water scarcity.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Over-extraction of water resources depletes
available water, causing scarcity.
Assertion (A): Plastic waste is a major environmental
pollutant.
Reason (R): Plastics are non-biodegradable and persist in the
environment for centuries.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Plastic waste is harmful to the environment due to
its non-biodegradable nature, leading to long-term pollution.
Assertion (A): Pesticides and herbicides can affect non-target
organisms.
Reason (R): These chemicals can be absorbed by organisms other
than the target species, causing harm.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Pesticides and herbicides can harm beneficial
insects, animals, and other organisms that were not the intended targets.
Assertion (A): Soil erosion is a significant environmental
issue.
Reason (R): Soil erosion leads to the loss of fertile topsoil,
affecting agricultural productivity.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Soil erosion results in the removal of fertile
soil, which is essential for agriculture, leading to decreased agricultural
productivity.
Assertion (A): Solid waste management is a major environmental
challenge.
Reason (R): Poor waste management practices lead to land and
water pollution, affecting health and ecosystems.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Ineffective waste management results in pollution,
impacting both the environment and human health.
Assertion (A): Carbon dioxide is a primary greenhouse gas
contributing to global warming.
Reason (R): Carbon dioxide traps heat in the Earth's
atmosphere, leading to an increase in global temperatures.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: CO2 is a major greenhouse gas that traps heat and
contributes to global warming by enhancing the greenhouse effect.
Assertion (A): Water pollution can lead to the spread of
waterborne diseases.
Reason (R): Contaminated water sources can harbor pathogens
that cause diseases like cholera and dysentery.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Polluted water contains harmful microorganisms
that cause waterborne diseases.
Assertion (A): The concept of ecological balance is essential
for a healthy environment.
Reason (R): Ecological balance ensures that natural systems
function in harmony, supporting life on Earth.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Ecological balance maintains the health of
ecosystems and ensures the survival of species.
Assertion (A): The depletion of fossil fuels is an
environmental issue.
Reason (R): Fossil fuel depletion contributes to energy
shortages and leads to increased environmental degradation.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The depletion of fossil fuels causes energy
shortages and environmental pollution, as alternative sources of energy are not
always available.
Assertion (A): Noise pollution can affect human health.
Reason (R): Prolonged exposure to high levels of noise can lead
to stress, hearing loss, and sleep disturbances.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Noise pollution can have detrimental effects on
human health, including psychological stress and physical damage to hearing.
Assertion (A): Biodiversity conservation is essential for
ecosystem stability.
Reason (R): A diverse range of species ensures that ecosystems
can recover from environmental changes and maintain their functions.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Biodiversity helps ecosystems remain stable and
resilient to changes, maintaining their ecological processes.
Assertion (A): Climate change can disrupt agricultural
patterns.
Reason (R): Changes in temperature and rainfall patterns affect
crop growth and yield.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Climate change alters weather patterns, impacting
agriculture by changing the suitability of regions for certain crops.
Assertion (A): E-waste is a growing environmental problem.
Reason (R): E-waste contains hazardous chemicals like lead,
mercury, and cadmium, which can leach into the environment.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: E-waste, if improperly disposed of, releases
harmful chemicals into the environment, contributing to pollution.
Assertion (A): The destruction of wetlands harms biodiversity.
Reason (R): Wetlands provide habitat for various species of
plants and animals, and their destruction leads to loss of habitat.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Wetlands are vital ecosystems that support diverse
species, and their destruction results in loss of biodiversity.
Assertion (A): The Paris Agreement aims to limit global warming
to below 2°C.
Reason (R): The agreement was signed by countries to commit to
reducing greenhouse gas emissions and curbing global temperature rise.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The Paris Agreement's goal is to limit global
warming to below 2°C, with commitments from countries to reduce emissions and
mitigate climate change.
Assertion (A): Forest fires contribute to atmospheric
pollution.
Reason (R): Forest fires release large amounts of carbon
dioxide and particulate matter into the atmosphere.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Forest fires release CO2, particulate matter, and
other pollutants, contributing to air pollution and global warming.
Assertion (A): Ozone depletion has led to an increase in skin
cancer cases.
Reason (R): Depletion of the ozone layer allows higher levels
of ultraviolet (UV) radiation to reach Earth's surface, which is harmful to
human skin.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The depletion of the ozone layer results in an
increase in UV radiation, which is a known cause of skin cancer.
Assertion (A): The greenhouse effect is harmful to the
environment.
Reason (R): The greenhouse effect leads to global warming by
trapping excessive heat in the Earth's atmosphere.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: While the natural greenhouse effect is essential
for life on Earth, human-induced enhancement of the greenhouse effect leads to
harmful global warming.
Assertion (A): The Earth's atmosphere is primarily composed of
nitrogen.
Reason (R): Nitrogen makes up about 78% of the Earth's
atmosphere, which is critical for various life processes.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Nitrogen is the most abundant gas in the
atmosphere and is essential for nitrogen fixation, which is important for plant
growth.
Assertion (A): Coral reefs are highly sensitive to changes in
environmental conditions.
Reason (R): Coral reefs require stable temperature, light, and
water conditions to thrive, and small changes can lead to coral bleaching.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Coral reefs are sensitive to environmental changes
like temperature and light, and these changes can result in coral bleaching,
which weakens and can kill the corals.
Assertion (A): Eutrophication is harmful to aquatic ecosystems.
Reason (R): Eutrophication leads to excessive growth of algae
that depletes oxygen levels in water, causing the death of aquatic life.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Eutrophication, caused by excess nutrients, leads
to algae blooms that consume oxygen, resulting in hypoxic conditions harmful to
aquatic life.
Assertion (A): Rainwater harvesting is an important practice
for conserving water.
Reason (R): Rainwater harvesting helps in recharging
groundwater and can reduce dependence on surface water sources.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Rainwater harvesting can store rainwater and help
recharge groundwater, making it an effective method to conserve water and reduce
pressure on existing water bodies.
Assertion (A): The Bhopal gas tragedy was a major environmental
disaster.
Reason (R): The release of methyl isocyanate gas from the Union
Carbide plant caused significant human health impacts and environmental
contamination.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The Bhopal gas leak caused severe health problems
for humans and the environment due to the toxic gas released into the
atmosphere.
Assertion (A): Plastic waste is a significant environmental
problem.
Reason (R): Plastics take hundreds of years to decompose and
often end up in oceans, harming marine life.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Plastics are non-biodegradable, and their
prolonged presence in the environment causes long-term pollution, particularly
in marine ecosystems.
Assertion (A): Environmental sustainability aims to meet the
needs of the present without compromising the ability of future generations to
meet their own needs.
Reason (R): This principle promotes responsible consumption,
resource management, and conservation efforts.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Sustainable development seeks to balance current
resource usage with the preservation of resources for future generations,
ensuring long-term ecological health.
Assertion (A): Greenhouse gases contribute to climate change.
Reason (R): Greenhouse gases like carbon dioxide, methane, and
nitrous oxide trap heat in the atmosphere, increasing global temperatures.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Greenhouse gases contribute to global warming by
trapping heat in the Earth's atmosphere, which accelerates climate change.
Assertion (A): The smog in large cities is a major cause of air
pollution.
Reason (R): Smog is formed when pollutants like sulfur dioxide
and nitrogen oxides react with sunlight, creating harmful particles.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Smog is a mixture of air pollutants that reacts
with sunlight to form harmful compounds, leading to poor air quality and health
risks.
Assertion (A): Organic farming is considered more
environmentally friendly than conventional farming.
Reason (R): Organic farming avoids the use of chemical
fertilizers and pesticides, promoting soil health and reducing environmental
pollution.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Organic farming is more sustainable as it uses
natural methods for pest control and soil management, leading to less
environmental harm compared to conventional methods.
Assertion (A): Ozone is a harmful pollutant when it is near the
Earth's surface.
Reason (R): Near the surface, ozone reacts with other chemicals
and can cause respiratory issues and other health problems.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Ground-level ozone is harmful as it contributes to
smog and can irritate the respiratory system.
Assertion (A): Afforestation is crucial for mitigating climate
change.
Reason (R): Trees absorb carbon dioxide during photosynthesis,
thus helping reduce the concentration of greenhouse gases in the atmosphere.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Planting trees helps in carbon sequestration,
reducing CO2 levels in the atmosphere and mitigating the impacts of climate
change.
Assertion (A): The Kyoto Protocol aimed at reducing greenhouse
gas emissions.
Reason (R): The Kyoto Protocol was an international treaty that
required industrialized countries to reduce their emissions of carbon dioxide
and other greenhouse gases.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The Kyoto Protocol established binding targets for
the reduction of greenhouse gas emissions from industrialized countries to
combat climate change.
Assertion (A): Deforestation leads to the loss of biodiversity.
Reason (R): Deforestation destroys habitats, which results in
the extinction of various plant and animal species.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Deforestation directly leads to habitat
destruction, which endangers species that depend on forests for survival.
Assertion (A): Urbanization increases the risk of environmental
degradation.
Reason (R): The expansion of cities leads to increased waste
generation, pollution, and the destruction of natural habitats.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Urbanization often results in more pollution,
habitat destruction, and a higher demand for resources, leading to environmental
degradation.
Assertion (A): Pesticides are used to protect crops from pests.
Reason (R): Pesticides kill harmful organisms that damage
crops, ensuring higher agricultural productivity.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Pesticides are effective in protecting crops from
pests, which helps in improving agricultural yield.
Assertion (A): The use of CFCs has led to the depletion of the
ozone layer.
Reason (R): CFCs break down ozone molecules in the
stratosphere, resulting in a thinning of the ozone layer.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: CFCs release chlorine atoms, which break down
ozone molecules, leading to ozone depletion.
Assertion (A): Wastewater treatment is essential to prevent
water pollution.
Reason (R): Untreated wastewater can contaminate water sources,
spreading disease and harming ecosystems.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Treating wastewater removes harmful pollutants,
preventing contamination of water sources and protecting human health and the
environment.
Assertion (A): Overfishing can lead to the collapse of marine
ecosystems.
Reason (R): Overfishing depletes fish populations, disrupting
the balance of marine food webs and harming biodiversity.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Overfishing reduces fish populations, leading to a
disruption in marine ecosystems and the loss of biodiversity.
Assertion (A): The Green Revolution contributed to an increase
in food production.
Reason (R): The use of high-yielding variety seeds, chemical
fertilizers, and pesticides during the Green Revolution significantly boosted
agricultural productivity.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: The Green Revolution used advanced techniques to
increase food production, helping meet the food demands of a growing population.
Assertion (A): Environmental pollution can be mitigated through
the use of renewable energy sources.
Reason (R): Renewable energy sources like wind and solar power
produce little to no pollution and reduce the reliance on fossil fuels.
Answer: (A) Both A and R are true, and R is the correct
explanation of A.
Explanation: Renewable energy sources reduce pollution by
decreasing the reliance on fossil fuels, which are major contributors to
environmental pollution.