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Q19 (IAS/2014) Environment & Ecology › Ecology & Ecosystem Basics › Biogeochemical cycles Official Key

Which of the following adds/add carbon dioxide to the carbon cycle on the planet Earth? 1. Volcanic action 2. Respiration 3. Photosynthesis 4. Decay of organic matter Select the correct answer using the code given below.

Result
Your answer: —  ·  Correct: C
Explanation

The correct answer is option C (1, 2 and 4 only).

Carbon dioxide in the atmosphere is produced by volcanic activity, respiration of plants and animals, and fossil fuel combustion by industries and transportation.[2] By process of respiration and decomposition of dead organic matter it returns back to atmosphere.[3] Therefore, volcanic action (statement 1), respiration (statement 2), and decay of organic matter (statement 4) all add carbon dioxide to the carbon cycle.

However, photosynthesis (statement 3) does the opposite. Carbon from the atmosphere moves to green plants by the process of photosynthesis, and then to animals.[3] Carbon dioxide is absorbed by producers to make carbohydrates in photosynthesis.[4] This means photosynthesis removes carbon dioxide from the atmosphere rather than adding it.

Therefore, only statements 1, 2, and 4 are processes that add carbon dioxide to the carbon cycle, making option C the correct answer.

Sources
  1. [1] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 1: BASIC CONCEPTS OF ENVIRONMENT AND ECOLOGY > Carbon and Oxygen Cycles > p. 20
  2. [2] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 1: BASIC CONCEPTS OF ENVIRONMENT AND ECOLOGY > Carbon and Oxygen Cycles > p. 20
  3. [3] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 2: Functions of an Ecosystem > L) The Carbon Cycle > p. 19
  4. [4] https://www.sciencedirect.com/topics/pharmacology-toxicology-and-pharmaceutical-science/environmental-toxicology
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Each bar shows the % of students who chose that option. Green bar = correct answer, blue outline = your choice.
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PROVENANCE & STUDY PATTERN
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Don’t just practise – reverse-engineer the question. This panel shows where this PYQ came from (books / web), how the examiner broke it into hidden statements, and which nearby micro-concepts you were supposed to learn from it. Treat it like an autopsy of the question: what might have triggered it, which exact lines in the book matter, and what linked ideas you should carry forward to future questions.
Q. Which of the following adds/add carbon dioxide to the carbon cycle on the planet Earth? 1. Volcanic action 2. Respiration 3. Photosynthes…
At a glance
Origin: Books + Current Affairs Fairness: Moderate fairness Books / CA: 7.5/10 · 2.5/10

This is a classic 'Sitter' found in Class VII NCERT. It tests the fundamental definition of Carbon Sources vs. Sinks. If you get this wrong, you are failing the baseline; no advanced book is needed, just clarity on basic biological processes.

How this question is built

This question can be broken into the following sub-statements. Tap a statement sentence to jump into its detailed analysis.

Statement 1
Does volcanic action add carbon dioxide to the carbon cycle on planet Earth?
Origin: Direct from books Fairness: Straightforward Book-answerable
From standard books
Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 1: BASIC CONCEPTS OF ENVIRONMENT AND ECOLOGY > Carbon and Oxygen Cycles > p. 20
Presence: 5/5
“tons as hydrocarbon molecules) or living and dead organic matter (2275 billion tons, as carbohydrate molecules). Carbon dioxide in the atmosphere is produced by volcanic activity, respiration of plants and animals, and fossil fuel combustion by industries and transportation.”
Why this source?
  • Explicitly states that atmospheric carbon dioxide is produced by volcanic activity alongside other sources.
  • Directly links volcanic activity to CO2 as a source in the modern carbon budget context.
Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 20: Earths Atmosphere > Hadean Eon (4,540 – 4,000 mya) > p. 270
Presence: 5/5
“• Volcanic outgassing created the primordial atmosphere. Outgassing from volcanism, supplemented by gases produced during the late heavy bombardment of Earth, produced the next atmosphere.• During the Late Heavy Bombardment (4 billion years ago), a disproportionately large number of asteroids collided with the early terrestrial planets including earth.• Over time, the Earth's surface solidified leaving behind hot volatiles which resulted in a heavy CO2 atmosphere with hydrogen, nitrogen, inert gases, and water vapour.• After the formation of oceans, dissolving in ocean water removed most CO2 from the atmosphere. Some CO2 reacted with metals to form carbonates that were deposited as sediments.• The early atmosphere contained almost no oxygen.”
Why this source?
  • Describes volcanic outgassing creating a primordial, CO2‑rich atmosphere—showing volcanism releases large CO2 quantities.
  • Explains the role of volcanic degassing in adding CO2 to Earth's atmosphere over geologic time.
Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 11: Volcanism > 1) Exhalative (Vapour Or Fumes) > p. 142
Presence: 4/5
“• Exhalative volcanism includes the discharge of material in gaseous forms, such as steam, fumes, HCl, ammonium chloride, sulphur dioxide, carbon dioxide, carbon monoxide, hydrogen sulphide, hydrogen, nitrogen, etc.• Volcanic gases may escape through vents which are in the form of hot springs, geysers, fumaroles (openings that emit steam and volcanic gases, such as sulfur dioxide and carbon dioxide) and solfataras (fumaroles where sulphur gases are dominant).• Exhalative volcanism indicates the volcano is reaching its extinction. Associated landforms are called sinter mounds, cones of precipitated minerals and mud volcanoes.”
Why this source?
  • Lists carbon dioxide among gases discharged in exhalative volcanism and emitted from fumaroles and vents.
  • Provides mechanistic detail on how volcanic systems emit CO2 to the surface/atmosphere.
Statement 2
Does respiration add carbon dioxide to the carbon cycle on planet Earth?
Origin: Direct from books Fairness: Straightforward Book-answerable
From standard books
Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 2: Functions of an Ecosystem > L) The Carbon Cycle > p. 19
Presence: 5/5
“ENVIRONMENT Carbon is present in the atmosphere, mainly in the form of carbon dioxide (CO<sub>2</sub>). Carbon cycle involves a continuous exchange of carbon between the atmosphere and organisms. Carbon from the atmosphere moves to green plants by the process of photosynthesis, and then to animals. By process of respiration and decomposition of dead organic matter it returns back to atmosphere. It is usually a short term cycle. Some carbon also enters a long term cycle. It accumulates as un-decomposed organic matter in the peaty layers of marshy soil or as insoluble carbonates in bottom sediments of aquatic systems which take a long time to be released.”
Why this source?
  • Explicitly states carbon moves from atmosphere to plants and then 'by process of respiration ... it returns back to atmosphere.'
  • Places respiration as a mechanism returning carbon to the atmospheric pool, i.e., adding CO2 to the cycle.
Science-Class VII . NCERT(Revised ed 2025) > Chapter 9: Life Processes in Animals > How does the exchange of gases happen? > p. 132
Presence: 5/5
“Oxygen helps break down glucose to release energy. This process is called respiration. The word equation of the process of respiration is as follows— Glucose + Oxygen Carbon dioxide + Water + Energy During breathing, we inhale air from our surroundings and exhale air having more carbon dioxide than the inhaled air. Note that not all the oxygen is used up (Fig. 9.13). Some other animals can use a larger fraction of the oxygen during respiration. This exchange of gases ensures that each segment of our body gets oxygen to produce energy and remove waste products. In simple words, breathing brings in oxygen and removes carbon dioxide, while respiration uses oxygen to break down food and release energy.”
Why this source?
  • Gives the respiration word equation showing glucose + oxygen → carbon dioxide + water + energy.
  • Notes exhaled air contains more CO2 than inhaled air, linking animal respiration to CO2 release to the atmosphere.
Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 1: BASIC CONCEPTS OF ENVIRONMENT AND ECOLOGY > Carbon and Oxygen Cycles > p. 20
Presence: 5/5
“tons as hydrocarbon molecules) or living and dead organic matter (2275 billion tons, as carbohydrate molecules). Carbon dioxide in the atmosphere is produced by volcanic activity, respiration of plants and animals, and fossil fuel combustion by industries and transportation.”
Why this source?
  • Lists 'respiration of plants and animals' explicitly as one of the producers of atmospheric carbon dioxide.
  • Positions respiration alongside other CO2 sources (volcanic activity, fossil fuel combustion), supporting its role in the carbon cycle.
Statement 3
Does photosynthesis add carbon dioxide to the carbon cycle on planet Earth?
Origin: Web / Current Affairs Fairness: CA heavy Web-answerable

Web source
Presence: 5/5
"Carbon dioxide is absorbed by producers to make carbohydrates in photosynthesis."
Why this source?
  • Explicitly states that producers absorb carbon dioxide during photosynthesis to make carbohydrates.
  • This shows photosynthesis removes CO2 from the atmosphere rather than adding it.
Web source
Presence: 4/5
"masses of Northern Hemisphere green in the spring and summer, they draw carbon out of the atmosphere."
Why this source?
  • Describes seasonal drawing of carbon out of the atmosphere by vegetation in spring and summer.
  • Implies photosynthetic growth pulls atmospheric CO2 into plant biomass instead of producing CO2.
Web source
Presence: 4/5
"With more atmospheric carbon dioxide available to convert to plant matter in photosynthesis, plants were able to grow more."
Why this source?
  • States atmospheric CO2 is converted to plant matter in photosynthesis (carbon fertilization example).
  • Shows photosynthesis channels CO2 into biomass, not as a source adding CO2 to the atmosphere.

Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 2: Functions of an Ecosystem > L) The Carbon Cycle > p. 19
Strength: 5/5
“ENVIRONMENT Carbon is present in the atmosphere, mainly in the form of carbon dioxide (CO<sub>2</sub>). Carbon cycle involves a continuous exchange of carbon between the atmosphere and organisms. Carbon from the atmosphere moves to green plants by the process of photosynthesis, and then to animals. By process of respiration and decomposition of dead organic matter it returns back to atmosphere. It is usually a short term cycle. Some carbon also enters a long term cycle. It accumulates as un-decomposed organic matter in the peaty layers of marshy soil or as insoluble carbonates in bottom sediments of aquatic systems which take a long time to be released.”
Why relevant

States carbon from the atmosphere moves to green plants by photosynthesis and later returns by respiration and decomposition, indicating photosynthesis removes atmospheric CO2 and stores it in organisms.

How to extend

A student could combine this with the basic idea of flux direction (if photosynthesis moves CO2 into biomass, it is not a source adding CO2 to the atmosphere) to judge whether photosynthesis is an atmospheric CO2 source or sink.

Science , class X (NCERT 2025 ed.) > Chapter 5: Life Processes > QUESTIONS > p. 82
Strength: 5/5
“Let us now see what actually happens during the process of photosynthesis. The following events occur during this process – • (i) Absorption of light energy by chlorophyll.• (ii) Conversion of light energy to chemical energy and splitting of water molecules into hydrogen and oxygen.• (iii) Reduction of carbon dioxide to carbohydrates. These steps need not take place one after the other immediately. For example, desert plants take up carbon dioxide at night and prepare an intermediate which is acted upon by the energy absorbed by the chlorophyll during the day. Let us see how each of the components of the above reaction are necessary for photosynthesis.”
Why relevant

Explains that photosynthesis involves reduction of carbon dioxide to carbohydrates, showing the chemical role of CO2 as a reactant consumed during the process.

How to extend

Using the chemical-role clue, a student can infer photosynthesis consumes CO2 (thus does not produce it) unless subsequent processes release it later.

Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 14: Marine Organisms > The Carbon Cycle and climate change > p. 208
Strength: 4/5
“• E Phytoplankton are responsible for most of the transfer of carbon dioxide from the atmosphere to the ocean. Carbon dioxide is consumed during photosynthesis, and the carbon is incorporated in the phytoplankton, just as carbon is stored in the wood and leaves of a tree. Most of the carbon is returned to near-surface waters when phytoplankton are eaten or decompose, but some falls into the ocean depths.”
Why relevant

Gives the example of phytoplankton consuming atmospheric CO2 during photosynthesis and incorporating carbon into biomass, then sometimes transporting carbon to depths—an explicit example of carbon removal from atmosphere.

How to extend

A student can extend this ocean example with a world map to see global scales of CO2 uptake by marine photosynthesis versus sources of CO2.

Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 21: Mitigation Strategies > 2r.2.1. Green Carbon > p. 282
Strength: 4/5
“• o Green carbon is carbon removed by photosynthesis and stored in the plants and soil of natural ecosystems and is a vital part of the global carbon cycle, • o Many plants and most crops have short lives and release much of their carbon at the end of each season, but forest biomass accumulates carbon over decades and centuries. • r Furthermore, forests can accumulate large amounts of CO2 in relatively short periods, typically several decades.”
Why relevant

Defines 'green carbon' as carbon removed by photosynthesis and stored in plants and soils, emphasizing photosynthesis as a carbon removal/storage process in the global cycle.

How to extend

Combine this definition with knowledge of ecosystem types (forests vs. crops) to estimate whether net photosynthetic uptake can outweigh releases and thus whether photosynthesis adds or removes CO2 overall.

Science-Class VII . NCERT(Revised ed 2025) > Chapter 10: Life Processes in Plants > 10.2.4 How do leaves exchange gases during photosynthesis? > p. 146
Strength: 4/5
“We now know that photosynthesis requires carbon dioxide, and oxygen is released in the process. Which part of the plant helps in the exchange of carbon dioxide and oxygen? Let us conduct an activity to understand where the exchange of gases takes place.”
Why relevant

Notes photosynthesis requires CO2 and releases O2, reinforcing that CO2 is an input to the photosynthetic process rather than an output.

How to extend

A student could pair this gas-exchange fact with measurements of atmospheric CO2 concentrations to assess photosynthesis' role as a sink at given times/places.

Statement 4
Does decay of organic matter add carbon dioxide to the carbon cycle on planet Earth?
Origin: Direct from books Fairness: Straightforward Book-answerable
From standard books
Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 2: Functions of an Ecosystem > L) The Carbon Cycle > p. 19
Presence: 5/5
“ENVIRONMENT Carbon is present in the atmosphere, mainly in the form of carbon dioxide (CO<sub>2</sub>). Carbon cycle involves a continuous exchange of carbon between the atmosphere and organisms. Carbon from the atmosphere moves to green plants by the process of photosynthesis, and then to animals. By process of respiration and decomposition of dead organic matter it returns back to atmosphere. It is usually a short term cycle. Some carbon also enters a long term cycle. It accumulates as un-decomposed organic matter in the peaty layers of marshy soil or as insoluble carbonates in bottom sediments of aquatic systems which take a long time to be released.”
Why this source?
  • Explicitly states that decomposition of dead organic matter returns carbon back to the atmosphere.
  • Presents decomposition alongside respiration as pathways that transfer carbon to atmospheric CO2.
Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 14: Marine Organisms > The Carbon Cycle and climate change > p. 208
Presence: 4/5
“• E Phytoplankton are responsible for most of the transfer of carbon dioxide from the atmosphere to the ocean. Carbon dioxide is consumed during photosynthesis, and the carbon is incorporated in the phytoplankton, just as carbon is stored in the wood and leaves of a tree. Most of the carbon is returned to near-surface waters when phytoplankton are eaten or decompose, but some falls into the ocean depths.”
Why this source?
  • Describes phytoplankton carbon being returned when they are eaten or decompose, indicating decomposition moves carbon back into the active pool.
  • Shows decomposition routes that recycle carbon from organisms to surface reservoirs (implying return to CO2 pool).
Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 1: BASIC CONCEPTS OF ENVIRONMENT AND ECOLOGY > Carbon and Oxygen Cycles > p. 20
Presence: 3/5
“tons as hydrocarbon molecules) or living and dead organic matter (2275 billion tons, as carbohydrate molecules). Carbon dioxide in the atmosphere is produced by volcanic activity, respiration of plants and animals, and fossil fuel combustion by industries and transportation.”
Why this source?
  • Lists respiration of plants and animals as a source of atmospheric CO2, supporting the broader idea that biological breakdown processes release CO2.
  • Identifies living and dead organic matter as a carbon pool linked to atmospheric CO2 production.
Pattern takeaway: UPSC Environment questions frequently test 'Functional Direction'—does a process increase or decrease a pollutant/element? Master the arrows (Up vs. Down) for Carbon, Nitrogen, and Water cycles.
How you should have studied
  1. [THE VERDICT]: Sitter. Directly solvable from NCERT Class VII Science (Chapter 10) or Shankar IAS Chapter 2.
  2. [THE CONCEPTUAL TRIGGER]: Biogeochemical Cycles (Gaseous vs. Sedimentary).
  3. [THE HORIZONTAL EXPANSION]: Memorize the flux directions for other cycles: Nitrogen (Fixation = Atmosphere to Soil; Denitrification = Soil to Atmosphere), Phosphorus (Sedimentary only; no atmospheric phase; main source is rock weathering), and Sulphur (Both gaseous via volcanoes/swamps and sedimentary). Know the specific bacteria: Rhizobium (Fixer) vs. Pseudomonas (Denitrifier).
  4. [THE STRATEGIC METACOGNITION]: Always classify environmental processes into 'Sources' (Add to atmosphere) and 'Sinks' (Remove from atmosphere). UPSC questions often hinge on this binary distinction rather than complex chemistry.
Concept hooks from this question
📌 Adjacent topic to master
S1
👉 Volcanic outgassing as a source of atmospheric CO2
💡 The insight

References state that volcanic degassing/outgassing produced CO2 and created a CO2‑rich early atmosphere, directly tying volcanism to carbon inputs.

High‑yield for questions on origin and evolution of the atmosphere, natural carbon sources, and long‑term carbon cycle. Helps answer linked questions about primordial atmosphere formation and geological CO2 fluxes; revise by mapping volcanic degassing → atmospheric composition across geologic time.

📚 Reading List :
  • Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 20: Earths Atmosphere > Hadean Eon (4,540 – 4,000 mya) > p. 270
  • Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 1: BASIC CONCEPTS OF ENVIRONMENT AND ECOLOGY > Carbon and Oxygen Cycles > p. 20
🔗 Anchor: "Does volcanic action add carbon dioxide to the carbon cycle on planet Earth?"
📌 Adjacent topic to master
S1
👉 Types and pathways of volcanic gas emissions
💡 The insight

Evidence lists exhalative volcanism and vents (fumaroles, solfataras) as direct pathways for CO2 release from Earth's interior to the atmosphere.

Useful for questions on volcanism impacts (climate, hazards, gas composition). Connects physical geography (volcanic processes) to biogeochemical cycling; study by linking gas types to volcanic features and environmental effects.

📚 Reading List :
  • Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 11: Volcanism > 1) Exhalative (Vapour Or Fumes) > p. 142
  • Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 11: Volcanism > Volcanism – Acid Rain, Ozone Destruction > p. 160
🔗 Anchor: "Does volcanic action add carbon dioxide to the carbon cycle on planet Earth?"
📌 Adjacent topic to master
S1
👉 Natural vs anthropogenic CO2 sources in the carbon cycle
💡 The insight

Sources identify volcanic activity alongside respiration and fossil fuel combustion as contributors to atmospheric CO2, highlighting multiple fluxes in the cycle.

Important for UPSC topics on climate change drivers and mitigation policy—distinguishing natural baseline fluxes from anthropogenic increases. Practice by comparing magnitudes, mechanisms, and policy implications across sources.

📚 Reading List :
  • Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 1: BASIC CONCEPTS OF ENVIRONMENT AND ECOLOGY > Carbon and Oxygen Cycles > p. 20
  • Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 17: Climate Change > 12.3.2 Carbon Dioxide > p. 255
  • Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 2: Functions of an Ecosystem > L) The Carbon Cycle > p. 19
🔗 Anchor: "Does volcanic action add carbon dioxide to the carbon cycle on planet Earth?"
📌 Adjacent topic to master
S2
👉 Respiration as a biological source of atmospheric CO2
💡 The insight

References explicitly identify respiration (plants and animals) as producing and returning CO2 to the atmosphere, which is the core of the statement.

High-yield: questions often ask about biotic sources and sinks of CO2 and the role of life processes in the carbon cycle. Links to photosynthesis, ecosystem energy flow, and climate-change sources. Prepare by memorizing respiration equations and comparing sources/sinks across ecosystems.

📚 Reading List :
  • Science-Class VII . NCERT(Revised ed 2025) > Chapter 9: Life Processes in Animals > How does the exchange of gases happen? > p. 132
  • Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 1: BASIC CONCEPTS OF ENVIRONMENT AND ECOLOGY > Carbon and Oxygen Cycles > p. 20
🔗 Anchor: "Does respiration add carbon dioxide to the carbon cycle on planet Earth?"
📌 Adjacent topic to master
S2
👉 Photosynthesis–respiration coupling in the carbon cycle
💡 The insight

Evidence shows photosynthesis takes up CO2 while respiration returns CO2, highlighting the dynamic balance within the carbon cycle.

Important for conceptual questions on net primary production, carbon fluxes, and ecosystem functioning — often tested in environment and ecology sections. Master by contrasting processes, flux directions, and net effects under different conditions.

📚 Reading List :
  • Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 2: Functions of an Ecosystem > L) The Carbon Cycle > p. 19
  • Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 1: BASIC CONCEPTS OF ENVIRONMENT AND ECOLOGY > Carbon and Oxygen Cycles > p. 19
  • Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 14: Marine Organisms > The Carbon Cycle and climate change > p. 208
🔗 Anchor: "Does respiration add carbon dioxide to the carbon cycle on planet Earth?"
📌 Adjacent topic to master
S2
👉 Short-term vs long-term carbon pools and fluxes
💡 The insight

References mention respiration/decomposition as part of the short-term cycle and accumulation in peaty layers or sediments as long-term pools.

Useful for questions on carbon sequestration, fossil fuels, and timescales of carbon release; connects to climate change mitigation topics. Study by categorizing pools (atmosphere, biosphere, ocean, lithosphere) and processes moving carbon between them.

📚 Reading List :
  • Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 2: Functions of an Ecosystem > L) The Carbon Cycle > p. 19
  • Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 14: Marine Organisms > The Carbon Cycle and climate change > p. 208
🔗 Anchor: "Does respiration add carbon dioxide to the carbon cycle on planet Earth?"
📌 Adjacent topic to master
S3
👉 Photosynthesis consumes atmospheric CO2
💡 The insight

Multiple references state that plants and phytoplankton take up CO2 during photosynthesis and reduce CO2 to carbohydrates.

Fundamental to questions on life processes, carbon fluxes, and climate science; often tested in ecology and environment sections. Masters should recall the basic inputs/outputs of photosynthesis and how CO2 is taken up rather than produced. Prepare by memorising the overall reaction and reading NCERT explanations and examples.

📚 Reading List :
  • Science-Class VII . NCERT(Revised ed 2025) > Chapter 10: Life Processes in Plants > 10.2.4 How do leaves exchange gases during photosynthesis? > p. 146
  • Science , class X (NCERT 2025 ed.) > Chapter 5: Life Processes > QUESTIONS > p. 82
  • Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 14: Marine Organisms > The Carbon Cycle and climate change > p. 208
🔗 Anchor: "Does photosynthesis add carbon dioxide to the carbon cycle on planet Earth?"
🌑 The Hidden Trap

The Phosphorus Cycle is the 'imperfect' cycle. Unlike Carbon or Nitrogen, it lacks a significant atmospheric component, making it a sedimentary cycle. A future question will likely ask: 'Which of the following cycles does NOT have a gaseous phase?'

⚡ Elimination Cheat Code

Use the 'Antagonistic Pair' logic. Respiration and Photosynthesis are biological opposites. If Respiration (2) adds CO2, Photosynthesis (3) must remove it. Therefore, they cannot both be correct answers for 'adding' CO2. Eliminate any option containing 3.

🔗 Mains Connection

Link this to Mains GS3 (Climate Change): 'Adding CO2' is the problem; 'Photosynthesis' is the solution (Carbon Sequestration). This connects to policy topics like REDD+, CAMPA funds (Afforestation), and Blue Carbon (Mangroves/Seagrasses).

✓ Thank you! We'll review this.

SIMILAR QUESTIONS

IAS · 2011 · Q48 Relevance score: 5.93

Consider the following 1. Photosynthesis 2. Respiration 3. Decay of organic matter 4. Volcanic action Which of the above add carbon dioxide to the carbon cycle on Earth ?

IAS · 2013 · Q9 Relevance score: -3.29

Which of the following adds/add nitrogen to the soil ? 1. Excretion of urea by animals 2. Burning of coal by man 3. Death of vegetation Select the correct answer using the codes given below.

IAS · 2011 · Q21 Relevance score: -3.74

Human activities in the recent past have caused the increased concentration of carbon dioxide in the atmosphere, but a lot of it does not remain in the lower atmosphere because of 1. Its escape into the outer stratosphere. 2. the photosynthesis by phytoplankton in the oceans. 3. the trapping of air in the polar ice caps. Which of the statements given above is/ are correct ?

IAS · 2017 · Q25 Relevance score: -3.92

In the context of mitigating the impending global warming due to anthropogenic emissions of carbon dioxide, which of the following can be the potential sites for carbon sequestration ? 1. Abandoned and uneconomic coal seams 2. Depleted oil and gas reservoirs 3. Subterranean deep saline formations Select the correct answer using the code given below :

NDA-II · 2008 · Q76 Relevance score: -4.11

Which of the following statements regarding carbon dioxide is/are correct? 1. It is prepared on large scale by the action of water on lime. 2. In the solid form it can be used as a refrigerant. Select the correct answer using the code given below :