Olympiad Test Level 2: Environmental Issues- 2 - Class 7 MCQ

Humans making greenhouse gases of our own:
Humans contribute to the production of greenhouse gases through various activities. The main sources include:
Burning fossil fuels in our cars:
- The combustion of gasoline and diesel fuels in vehicles releases carbon dioxide (CO2) into the atmosphere.
- This is a significant contributor to greenhouse gas emissions, as transportation is a major source of CO2 emissions globally.
Burning forests:
- Deforestation and the burning of forests contribute to greenhouse gas emissions.
- When trees are burned, carbon stored in the vegetation is released as carbon dioxide, adding to the greenhouse effect.
Large-scale agriculture:
- Agricultural practices, such as livestock farming and rice cultivation, release greenhouse gases.
- Livestock produce methane (CH4), a potent greenhouse gas, through their digestive processes.
- Rice cultivation in flooded fields produces methane due to anaerobic conditions.
All of these:
- Each of the activities mentioned above contributes to the overall production of greenhouse gases.
- The combination of burning fossil fuels, burning forests, and large-scale agriculture significantly increases the concentration of greenhouse gases in the atmosphere.
It is important to note that these human activities significantly contribute to climate change and global warming. Efforts to reduce greenhouse gas emissions and transition to cleaner and more sustainable energy sources are essential in mitigating the impacts of climate change.

Visually Striking Evidence of Global Warming
There are several visually striking evidences of global warming, but the most prominent one is the rapid melting of glacial ice on nearly every continent. This can be observed through various visual indicators such as satellite images, photographs, and scientific studies. Here are the key points to consider:
1. Glacial Ice Melting:
- Glacial ice is melting at an alarming rate due to increasing global temperatures.
- This can be observed through images showing the shrinkage of glaciers over time.
- Glacial retreat is especially noticeable in regions like the Arctic, Antarctica, the Himalayas, and the Alps.
2. Impact on Sea Levels:
- The melting of glacial ice contributes to rising sea levels.
- Satellite images provide visual evidence of coastal areas being submerged or eroded.
3. Disappearing Ice Caps:
- The melting of ice caps, such as those in the Arctic, is a visible sign of global warming.
- Satellite imagery shows a significant reduction in the extent of sea ice in the Arctic region.
4. Changes in Landscapes:
- Glacial meltwater forms lakes, rivers, and even new landforms, altering the landscape.
- Images of newly formed lakes and altered river courses provide visual proof of glacial melting.
5. Extreme Weather Events:
- While not directly related to glacial ice melting, extreme weather events can also be visually striking evidence of global warming.
- Images of hurricanes, heatwaves, droughts, and floods show the impact of climate change on weather patterns.
In conclusion, the most visually striking evidence of global warming is the rapid melting of glacial ice on nearly every continent. This phenomenon can be observed through various visual indicators, including satellite images, photographs, and scientific studies. The shrinking glaciers, rising sea levels, disappearing ice caps, changes in landscapes, and extreme weather events all provide compelling visual proof of the effects of global warming.

Greenhouse effect refers to:
The greenhouse effect is a natural process that occurs in the Earth's atmosphere. It is responsible for keeping the planet warm enough to sustain life. Here is a detailed explanation of what the greenhouse effect entails:
1. Definition:
- The greenhouse effect is the ability of certain atmospheric gases to trap heat and keep the planet relatively warm.
2. Atmospheric Gases:
- Greenhouse gases, such as carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and water vapor (H2O), play a crucial role in the greenhouse effect.
3. Mechanism:
- When sunlight reaches the Earth's surface, it is absorbed and re-emitted as heat energy.
- Greenhouse gases in the atmosphere absorb this heat energy and re-radiate it in all directions, including back towards the Earth's surface.
- This process traps some of the heat, preventing it from escaping into space and subsequently warming the planet.
4. Natural and Enhanced Greenhouse Effect:
- The natural greenhouse effect is essential for maintaining a habitable temperature on Earth.
- However, human activities, such as burning fossil fuels and deforestation, have increased the concentration of greenhouse gases in the atmosphere, leading to an enhanced greenhouse effect.
- The enhanced greenhouse effect is contributing to global warming and climate change.
5. Consequences:
- The greenhouse effect and subsequent global warming have various impacts on the Earth's climate system, including rising temperatures, melting ice caps and glaciers, sea-level rise, extreme weather events, and disruptions to ecosystems.
6. Mitigation:
- To mitigate the effects of the enhanced greenhouse effect, it is necessary to reduce greenhouse gas emissions by transitioning to renewable energy sources, improving energy efficiency, and adopting sustainable practices.
In conclusion, the greenhouse effect refers to the ability of certain atmospheric gases to trap heat and keep the planet relatively warm. This natural process is vital for sustaining life on Earth, but human activities have intensified it, leading to global warming and climate change. It is crucial to take measures to mitigate the enhanced greenhouse effect and ensure a sustainable future.

Primary Contributors to the Greenhouse Effect:
- Carbon dioxide (CO2): This is the most significant greenhouse gas and is primarily released through the burning of fossil fuels, deforestation, and other industrial processes.
- Methane (CH4): This gas is released during the production and transport of coal, oil, and natural gas. It is also emitted by livestock and other agricultural practices, as well as the decay of organic waste in landfills.
- Carbon monoxide (CO): Although carbon monoxide is a greenhouse gas, it is not considered a primary contributor to the greenhouse effect. It is primarily released through incomplete combustion of fossil fuels and biomass burning.
- Chlorofluorocarbons (CFCs): These synthetic compounds were widely used in refrigerants, aerosol propellants, and foam-blowing agents. However, they have been phased out due to their harmful effects on the ozone layer. While CFCs do contribute to global warming, they are not considered a primary greenhouse gas.
Explanation:
The correct answer is C: Chlorofluorocarbons (CFCs). While CFCs do contribute to global warming, they are not considered a primary contributor to the greenhouse effect. Carbon dioxide, methane, and carbon monoxide are all primary greenhouse gases that trap heat in the Earth's atmosphere, leading to the greenhouse effect and climate change. CFCs, on the other hand, have been phased out due to their harmful effects on the ozone layer and are no longer widely used.

Definition of Global warming:
Global warming refers to the long-term increase in Earth's surface temperature due to the effect of greenhouse gases.
Explanation:
Global warming is a complex phenomenon that is primarily caused by human activities, especially the burning of fossil fuels such as coal, oil, and natural gas. The release of greenhouse gases, including carbon dioxide, methane, and nitrous oxide, into the atmosphere traps heat and leads to a gradual increase in Earth's surface temperature. This has several detrimental effects on the planet and its ecosystems.
Key Points:
- Global warming is the increase in Earth's surface temperature.
- It is caused by the effect of greenhouse gases.
- Greenhouse gases trap heat in the atmosphere, leading to a warming effect.
- Human activities, particularly the burning of fossil fuels, contribute significantly to global warming.
- Global warming has various adverse impacts on the environment, including rising sea levels, melting ice caps, more frequent and severe weather events, and disruptions to ecosystems.
Conclusion:
In summary, global warming is the long-term increase in Earth's surface temperature due to the effect of greenhouse gases. It is a significant environmental issue that requires global efforts to mitigate its impacts and transition towards more sustainable practices.

Solution to Get Rid of Non-Biodegradable Waste: Burying
There are various methods to get rid of non-biodegradable waste, but burying is considered one of the best solutions due to its effectiveness and environmental impact. Here is a detailed explanation of why burying is a suitable option:
1. Landfill:
- Non-biodegradable waste can be disposed of in landfills, which are specially designed areas where waste is buried.
- Landfills are engineered to minimize the impact on the environment and prevent contamination of soil and groundwater.
2. Segregation and Compaction:
- Before burying, waste can be segregated to separate recyclable materials, reducing the amount of waste going into the landfill.
- Waste is then compacted to maximize the use of available space in the landfill.
3. Long-term Storage:
- Burying waste provides long-term storage, preventing it from being exposed to the environment and potentially causing harm.
- It also helps in reducing the risk of pests, odor, and the spread of diseases associated with waste.
4. Methane Capture:
- Landfills can capture and utilize the methane gas produced by buried waste.
- Methane is a potent greenhouse gas, so capturing and utilizing it helps reduce its impact on climate change.
5. Environmental Protection Measures:
- Modern landfills are designed with liners and leachate collection systems to prevent the contamination of soil and groundwater.
- Regular monitoring and maintenance of landfills ensure proper waste management and environmental protection.
6. Cost-effectiveness:
- Burying waste in landfills is generally a cost-effective method as compared to other alternatives like incineration or recycling.
Overall, burying non-biodegradable waste in landfills is a viable solution that ensures proper waste management, minimizes environmental impact, and maximizes the use of available resources. However, it is important to note that reducing waste generation and promoting recycling should always be prioritized to minimize the amount of waste that needs to be buried.

Organism that is most likely to produce green gases such as nitrous oxide:
Answer: D - Green plants

Explanation:

• Green plants are the primary producers in the ecosystem and play a vital role in the carbon cycle.


• During the process of photosynthesis, green plants take in carbon dioxide from the atmosphere and release oxygen as a byproduct.


• However, during certain conditions, green plants can also produce greenhouse gases such as nitrous oxide (N2O).


• Nitrous oxide is emitted from plants through a process called denitrification, which occurs in the soil.


• The denitrification process involves the conversion of nitrate (NO3-) in the soil to nitrous oxide (N2O) by bacteria.


• This process is more likely to occur in environments with low oxygen levels or excess nitrogen.


• Green plants release nitrous oxide into the atmosphere, contributing to the greenhouse effect and climate change.

Therefore, out of the given options, green plants are most likely to produce green gases such as nitrous oxide.

Causes of the 2004 Indian Ocean tsunami:

• Underwater Earthquake: The tsunami was triggered by a massive underwater earthquake with a magnitude of 9.1-9.3 on the Richter scale. The earthquake occurred off the west coast of northern Sumatra, Indonesia.


• Subduction Zone: The earthquake occurred along a subduction zone, where one tectonic plate is forced beneath another. In this case, the Indian Plate was subducting beneath the Burma Plate, causing the seafloor to uplift and displace a large volume of water.


• Vertical Displacement: The earthquake caused a vertical displacement of the seafloor, resulting in the formation of a tsunami wave. The sudden movement of the seafloor pushed the water column above it, generating a series of powerful waves.


• Propagation: The tsunami waves radiated outward from the epicenter in a circular pattern, traveling across the Indian Ocean at high speeds.


• Impact on South India: The tsunami waves reached the eastern coast of South India, causing widespread devastation. Coastal areas were flooded, homes and infrastructure were destroyed, and thousands of lives were lost.


• Global Impact: The tsunami waves traveled across the Indian Ocean, affecting countries as far as South Africa. The waves dissipated as they traveled, but still caused significant damage and loss of life in coastal regions.

In conclusion, the 2004 Indian Ocean tsunami was caused by an underwater earthquake along a subduction zone off the coast of Indonesia. The earthquake resulted in a vertical displacement of the seafloor, generating powerful tsunami waves that propagated across the Indian Ocean and impacted coastal regions, including South India and even South Africa.

The correct answer is D: Cooking oil, ghee, mayonnaise, and fats should be poured down the drains.
Water pollution is a serious environmental issue that can have harmful effects on aquatic ecosystems and human health. There are various ways to prevent water pollution, but pouring cooking oil, ghee, mayonnaise, and fats down the drains is not one of them.
Here are the correct ways to prevent water pollution:
A: Proper storage and disposal of toxic products:
- Household chemicals and cleaning agents should be stored in a safe and secure manner.
- Proper disposal methods should be followed to prevent these toxic products from entering water sources.
B: Safe disposal of medications and drugs:
- Pills, liquid or powder medications, and drugs should not be thrown into the drain.
- These substances can contaminate water sources and harm aquatic life.
- Proper disposal methods, such as returning unused medications to pharmacies or participating in drug take-back programs, should be followed.
C: Use of natural fertilizers and pesticides:
- Farmers should try to use natural fertilizers and pesticides instead of chemical-based ones.
- Chemical fertilizers and pesticides can seep into water sources and cause pollution.
- Natural alternatives, such as compost and biological pest control methods, can be used to minimize water pollution.
D: Avoid pouring cooking oil, ghee, mayonnaise, and fats down the drains:
- These substances can clog pipes and cause blockages in the sewage system.
- They can also contaminate water sources and harm aquatic life.
- Proper disposal methods, such as collecting and recycling used cooking oil, should be followed.

Natural Resources

Resources that we find in nature and are used without much modification are called natural resources. These resources are essential for human survival and economic development. Examples of natural resources include:

• Water: Rivers, lakes, and groundwater are natural resources that are used for drinking, irrigation, and power generation.


• Air: The atmosphere is a natural resource that provides oxygen for breathing and is vital for climate regulation.


• Forests: Trees and vegetation are natural resources that provide timber, food, and habitat for wildlife.


• Minerals: Natural resources such as coal, oil, natural gas, and metals like iron and copper are used for energy production and manufacturing.


• Soil: Land is a natural resource that provides space for agriculture and construction.


• Sunlight: Solar energy is a natural resource that is used for power generation and heating.

Natural resources can be categorized further into renewable and exhaustible resources:

• Renewable resources: These resources are naturally replenished or can be replaced within a human lifespan, such as sunlight, wind, water, and forests.


• Exhaustible resources: These resources are finite and cannot be replenished within a short time, such as fossil fuels (coal, oil, natural gas) and minerals. Their availability is limited, and their extraction can have environmental consequences.

Understanding and managing natural resources sustainably is crucial to ensure their availability for future generations and to minimize negative impacts on the environment.