Q.A plastic sack manufacturer in Bengaluru, Ahmed Khan has managed to find an ideal solution to the problem of plastic waste. Explain in five steps the efforts of Ahmed Khan to meet the challenges of solid waste management.
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🔒 Start your 14-day free trial to unlock the full solution →Part (a)Concept understanding — Health Effects
Health Effects — A First Look
Think about the last time you drank water from a roadside stall during summer. Your mind probably weighed two things: the immediate thirst, and the vague worry about whether the water was clean. That worry — that something in the environment might harm your body — is exactly what "health effects" means.
In simple terms, health effects are the changes — good or bad — that happen to your body and mind when you are exposed to something in your surroundings. That "something" could be polluted air, contaminated food, loud noise, stress at work, or even a new medicine. The key idea is that your environment and your health are not separate; they are constantly interacting.
The precise meaning
The NCERT textbook (Class 12, Business Studies, Chapter 12 — Consumer Protection) introduces health effects in the context of consumer awareness. When you buy a product or use a service, you have a right to know whether it will harm you. Health effects, therefore, refer to the physical or mental consequences that arise from using a product, consuming a food item, or living in a particular environment.
These effects can be:
- Immediate — like a headache from a chemical smell, or food poisoning from stale food.
- Long-term — like lung disease from years of breathing polluted air, or hearing loss from constant loud music.
- Direct — like a burn from a faulty appliance.
- Indirect — like stress and anxiety caused by unsafe living conditions.
Health effects are not just about illness. They also include positive effects — for example, the health benefit of drinking clean water or using a well-designed ergonomic chair. The term is neutral; it simply describes the outcome of an exposure.
Why it matters for a commerce/humanities student
You might think health effects belong only in biology or medicine. But in commerce and humanities, they are central to consumer protection, business ethics, and public policy.
Consider a company that sells packaged food. If the food contains a harmful preservative, the health effect on consumers could be serious — and the company faces legal action, loss of reputation, and financial penalties. That is why the Consumer Protection Act, 2019, gives you the right to safety — meaning products must not cause harm under normal use.
Similarly, in economics, health effects are part of externalities. A factory that pollutes a river creates a negative health effect for people downstream — but the factory does not pay for that harm. Understanding health effects helps you see why governments regulate industries and why consumers need protection.
A few key points to remember
- Health effects can be physical (like a rash, cough, or injury) or mental (like anxiety, depression, or stress).
- They can arise from products (food, medicines, electronics), services (healthcare, transport), or environmental factors (air, water, noise). …
Part (b)Concept understanding — Ecological Pyramid
Picture a real pyramid -- wide at the base, narrowing all the way up to a single point at the top. Ecologists borrow exactly this shape to describe something that has nothing to do with stone: how numbers, weight (biomass), or energy are distributed across the feeding levels of a food chain. This visual model is called an ecological pyramid.
Every ecological pyramid works the same way. In your NCERT textbook (Class 12 Biology, Chapter 12, Ecosystem, section 12.5), the base always represents the producers -- the first trophic level -- and each successive tier above it represents the next trophic level up (herbivores, then primary carnivores, then secondary or top carnivores), with the apex representing the top-level consumer. Three distinct types are studied, because the same food-chain relationship can be measured in three different ways:
- Pyramid of numbers -- plots the count of individual organisms at each trophic level. NCERT's own grassland example is dramatic: nearly 6 million producer plants are needed to support just three top-carnivores at the apex.
- Pyramid of biomass -- plots the standing crop (usually expressed as dry weight, which is more accurate than fresh weight) of organisms at each level, rather than headcount.
- Pyramid of energy -- plots the amount of energy present at each trophic level, measured per unit area, usually annually.
In most ecosystems, all three pyramids come out upright -- producers are more numerous and have more biomass than herbivores, and herbivores more than carnivores -- because energy shrinks at every step up the food chain (the same 10 per cent law behind energy flow: only about 10 per cent of the energy at one trophic level is transferred to the next).
When a pyramid turns upside down -- numbers and biomass pyramids don't always come out upright, and NCERT points to genuine exceptions you're expected to reason through, not just memorise:
- A single large tree can support so many feeding insects that a pyramid of numbers built around it is inverted right at the base -- one producer, many primary consumers.
- The pyramid of biomass in the sea is commonly inverted: at any given moment the standing crop of tiny, fast-reproducing phytoplankton is small, yet it is turning over fast enough to support a much larger standing crop of the zooplankton feeding on it.
The pyramid of energy is the one type that is never inverted -- it is always upright, in every ecosystem, without exception. Energy is lost as heat at every transfer between trophic levels (unlike nutrients, it is never recycled back), so the level below always has to hold more usable energy than the level feeding on it. …
Part (a)
Ahmed Khan, a plastic-sack manufacturer in Bengaluru, tackled plastic waste by developing "Polyblend," a fine powder of recycled modified plastic used along with bitumen for road-laying. His effort can be described in five steps:
- Collection: discarded plastic waste (bags, wrappers, etc.) is gathered, mostly from municipal/segregation sources.
- Cleaning: the collected plastic is washed to remove dirt and contaminants.
- Grinding into fine powder (Polyblend): the clean plastic is shredded/ground into a very fine powder.
- Mixing with bitumen: the Polyblend powder is mixed with heated bitumen; the plastic coats the aggregate and improves the binding. …
Part (a): Ahmed Khan created "Polyblend" and used plastic waste in road-making in five steps - collect, clean, grind to fine powder, mix with bitumen, lay roads - turning waste into a durable resource.
Part (b): an ecological pyramid represents number, biomass or energy across trophic levels; its limitations include ignoring species in multiple trophic levels and excluding decomposers; the biomass pyramid is inverted in a pond/sea where small phytoplankton support a larger biomass of consumers.
Part (a)
Ahmed Khan, a plastic-sack manufacturer in Bengaluru, found a practical solution to the growing problem of plastic waste by inventing "Polyblend," a fine powder of recycled modified plastic. Mixed with bitumen, Polyblend is used to lay roads, so the non-biodegradable plastic that normally chokes landfills is instead consumed usefully. His effort can be explained in five steps:
- Collection of plastic waste. Discarded plastic (carry bags, wrappers, sacks and other refuse) is collected, largely from municipal waste and segregation units, giving a steady supply of material that would otherwise be dumped or burned.
- Cleaning. The collected plastic is thoroughly washed to remove dirt, food residue and other contaminants, since clean plastic is needed for a good final product.
- Grinding into a fine powder (Polyblend). The cleaned plastic is shredded and ground into a very fine powder. This is the key innovation — the "Polyblend" that can blend uniformly with road-making material.
- Mixing with bitumen. The Polyblend powder is mixed with heated bitumen (the binder used in road construction). The plastic melts slightly and coats the stone aggregate, improving the binding and water resistance of the mix.
- Laying roads. The plastic-bitumen mixture is used to construct roads. These roads are stronger, more durable and more water-resistant, and each kilometre uses up a large quantity of waste plastic — solving a disposal problem while improving infrastructure. …
Showing the 12 most recent of 29 on this concept.
- CBSE 2026Set 57/3/11 markMCQQ.Every trophic level has a certain mass of living material at a particular time. What is it called ? (A) Standing crop (B) Primary productivity (C) Standing state (D) Ecological efficiency
›Reveal solutionSolution
The mass of living material present at each trophic level at any given moment is called the standing crop.
When ecologists study how energy and matter flow through an ecosystem, they need a way to measure what's actually present at each feeding level at any snapshot in time. Imagine walking into a grassland and asking: how much grass is there right now? How many grasshoppers? How many birds feeding on those grasshoppers? Each of these groups represents a trophic level, and the total mass of all organisms at that level, measured at a particular moment, has a specific name.
This measurement is called the standing crop. It represents the biomass—the total dry weight of all living organisms—at a given trophic level at a specific point in time. Think of it as taking inventory of life: if you could weigh all the producers, or all the primary consumers, or all the secondary consumers in an ecosystem right now, that weight would be the standing crop for that level.
The standing crop is crucial because it forms the basis of ecological pyramids. When we draw a pyramid of biomass, each bar represents the standing crop at that trophic level. In most terrestrial ecosystems, you'll see a classic pyramid shape—lots of plant biomass at the base, less herbivore biomass in the middle, and even less carnivore biomass at the top. But in some aquatic ecosystems, the pyramid can be inverted because phytoplankton (though small in total mass at any moment) reproduce so rapidly that they can support a larger standing crop of zooplankton. …
- CBSE 2026Set 57/3/11 markMCQQ.Some statements regarding drugs and alcohol are given below :(i) Adolescents are more vulnerable to peer pressure.(ii) Drug addiction leads to increased tolerance level of the receptors present in our body.(iii) Alcohol affects the central nervous system.(iv) Excessive use of drugs helps to increase energy.(v) Anabolic steroids decrease aggressiveness. Choose the option with correct statement(s). (A) Statements (i),(iv) and(v) are correct (B) Statements (i),(ii) and(iii) are correct (C) Only statements(i) and(v) are correct (D) Only statement(iii) is correct
›Reveal solutionSolution
Only statements (i), (ii), and (iii) are factually correct; statements (iv) and (v) are false.
Let’s look at each statement one by one, because this question tests not just memory but a clear understanding of how drugs and alcohol actually work in the body.
Statement (i) — Adolescents are more vulnerable to peer pressure. This is widely accepted. The teenage brain is still developing, especially the prefrontal cortex responsible for impulse control and long-term decision-making. At the same time, social belonging becomes intensely important. That combination makes adolescents genuinely more susceptible to peer influence, including pressure to try drugs or alcohol. So this statement is correct.
Statement (ii) — Drug addiction leads to increased tolerance level of the receptors present in our body. This is a precise and accurate point. With repeated use of many drugs, the body adapts. Receptors on nerve cells become less sensitive or reduce in number, so the user needs a larger dose to feel the same effect. That is exactly what tolerance means — it is a physiological change, not just a psychological one. So this statement is correct.
Statement (iii) — Alcohol affects the central nervous system. Absolutely. Alcohol is a central nervous system depressant. It slows down brain activity, impairs coordination, judgment, and reaction time, and in large amounts can lead to unconsciousness or even respiratory failure. This is one of the most basic facts about alcohol. So this statement is correct. …
- CBSE 2026Set BOTANY1 markMCQQ.In an ecological pyramid of energy, _____ trophic level is occupied by the herbivores.(a) first(b) second(c) third(d) fourth
›Reveal solutionSolution
In any ecological pyramid (of energy, numbers, or biomass), producers occupy the first trophic level and herbivores (primary consumers) occupy the second.
An ecological pyramid represents the trophic structure of an ecosystem as successive trophic levels, arranged from producers at the base upward through consumers. The general sequence is:
- First trophic level - producers (green plants/algae), which fix solar energy through photosynthesis.
- Second trophic level - primary consumers, i.e. herbivores, which feed directly on producers (e.g. a grasshopper eating grass, or zooplankton eating phytoplankton).
- Third trophic level - secondary consumers (primary carnivores), which eat herbivores.
- Fourth trophic level - tertiary consumers (secondary/top carnivores), which eat other carnivores. …
- CBSE 2026Set ANNUAL1 markMCQQ.Pyramid of biomass in the sea are generally(a) Straight(b) Upright(c) Invert(d) All kinds
›Reveal solutionSolution
Unlike a pond or forest, the biomass pyramid in the sea is typically inverted because the producers (phytoplankton) have very small standing biomass but a very high turnover/reproduction rate.
In a marine ecosystem, producer biomass at any instant (phytoplankton) is small, since they are rapidly consumed and have short life spans and fast reproduction, while the standing biomass of consumers (zooplankton, fish etc.) at higher trophic levels is comparatively larger. So when biomass is plo …
- CBSE 2026Set ANNUAL1 markMCQQ.The diagram given below shows the type of an ecological pyramid. A sharp decrease is seen at higher trophic levels. Choose the correct option for the indication of this pyramid.(a) The energy is increasing at higher trophic level(b) The energy is same in all trophic levels(c) The energy is constant in all trophic levels(d) The energy is decreasing at higher trophic level
›Reveal solutionSolution
Energy decreases progressively at each successive trophic level because a large fraction (~90%) is lost as heat/respiration at every transfer (the 10% law), so the pyramid of energy is always upright and each tier is smaller than the one below it.
At each trophic level, organisms use most of the energy they receive for their own respiration, movement and metabolism, and only a small fraction (roughly 10%, per Lindeman's 10% law) is stored in biomass and passed on to the next trophic level when consumed. This progressive energy loss means producers (tier 1, widest base) always have the most energy, prim …
- CBSE 2026Set ANNUAL1 markMCQQ.Assertion : The pyramid of energy is always upright. Reason : At each trophic level some energy is lost as heat.(a) If both Assertion and Reason are true and Reason is a correct explanation of the Assertion.(b) If both Assertion and Reason are true but Reason is not a correct explanation of the Assertion.(c) If Assertion is true but Reason is false.(d) If both Assertion and Reason are false.
›Reveal solutionSolution
Both statements are true and the loss of energy as heat at each trophic level is exactly why the energy pyramid is always upright — so the answer is (A).
Assertion: The pyramid of energy is always upright — TRUE. Unlike pyramids of number or biomass (which can be inverted), the energy pyramid can never be inverted.
Reason: At each trophic level some energy is lost as heat — TRUE. As energy flows from one trophic level to the next, only about 10% is transferred; the rest is lost mainly as heat during respiration and metabolism (Lindeman's 10% law).
…
- CBSE 2026Set ANNUAL1 markQ.“Smoking causes oxygen deficiency in human body”. Justify the statement.
›Reveal solutionSolution
Carbon monoxide in cigarette smoke binds haemoglobin more strongly than oxygen, reducing oxygen transport — so smoking causes oxygen deficiency.
Tobacco smoke contains carbon monoxide (CO) and nicotine. Haemoglobin, the oxygen-carrying pigment of blood, has a much higher affinity for CO than for oxygen (about 200 times). When a person smokes, CO binds haemoglobin to form stable carboxyhaemoglobin, so that much less haemoglobin is available to bind and transport oxygen.
…
- CBSE 2026Set ANNUAL1 markQ.Write True or False. Cocaine is obtained from the leaves of the Erythroxylum coca and acts as a stimulant on the central nervous system.
›Reveal solutionSolution
True — cocaine comes from the coca plant (Erythroxylum coca) and is a CNS stimulant.
In the CBSE/NCERT Human Health and Disease chapter (drugs and alcohol abuse), cocaine is extracted from the leaves of Erythroxylum coca, native to South America. It interferes with dopamine transport in the brain and acts as a powerful **stimulant …
- CBSE 2025Set ANNUAL1 markMCQQ.The pyramid of energy is-(a) Always inverted(b) Always upright(c) Some times uprighted and some time inverted(d) None of these
›Reveal solutionSolution
The pyramid of energy is always upright because energy loss occurs at every trophic level.
As per the second law of thermodynamics, energy flow through an ecosystem is unidirectional and a substantial part of the energy is always lost as heat (through respiration) at every trophic transfer. Because of this progressive loss, the amount of energy available decreases from producers to successive consumer levels. Hence, when energy content is plotted against trophic level, the pyramid of energy always ha …
- CBSE 2025Set ANNUAL1 markQ.The pyramid of _________ is always upright and can never be inverted.
›Reveal solutionSolution
Because energy is progressively lost as heat at each trophic transfer, the pyramid of energy can never be inverted; it is always upright, unlike pyramids of numbers or biomass in some ecosystems.
Ecological pyramids can be of three types: pyramid of number, pyramid of biomass, and pyramid of energy.
- Pyramids of number and biomass may sometimes be inverted (e.g., a pyramid of numbers is inverted in a tree ecosystem where one tree supports many insects; a pyramid of biomass is inverted in a pond/sea ecosystem where a small standing crop of phytoplankton supports a larger biomass of zooplankton and fish). …
- CBSE 2025Set ANNUAL1 markMCQQ.An inverted pyramid of biomass can be found in(a) deserts(b) marine(c) grassland(d) tundra
›Reveal solutionSolution
Marine ecosystems commonly show an inverted biomass pyramid, since the standing crop of tiny, fast-reproducing phytoplankton is much smaller than the biomass of the zooplankton and fish that depend on it.
A pyramid of biomass represents the total mass of living organisms at each trophic level. It is usually upright in most terrestrial ecosystems (like deserts, grasslands, and tundra), since producer biomass exceeds that of the consumers feeding on it. However, in marine (e.g., open ocean) ecosystems, the producers (phytoplankton) have a very small standing biomass at any given time (because they are tiny, short-lived, and reproduce rapidly, being continuously consumed and replac …
- CBSE 2024Set 57/2/11 markMCQQ.The pyramid of biomass in sea is generally inverted because in sea : (A) Biomass of fishes exceeds that of phytoplankton. (B) Number of phytoplanktons is more. (C) Number of phytoplanktons is less. (D) Large fishes feed on small fishes.
›Reveal solutionSolution
The pyramid of biomass in the sea is inverted because the standing crop (biomass at any given moment) of phytoplankton is smaller than that of zooplankton and fish, even though phytoplankton reproduce rapidly and support the entire food chain.
An ecological pyramid is a graphical representation that shows the relationship between different trophic levels in an ecosystem. When we talk about a pyramid of biomass, we're measuring the total dry weight of all living organisms at each level at a particular moment in time — what ecologists call the "standing crop."
In most terrestrial ecosystems, the pyramid of biomass is upright. Think of a forest: the biomass of trees (producers) far exceeds that of herbivores, which in turn exceeds that of carnivores. This makes intuitive sense — you need a large base of producers to support the levels above.
But marine ecosystems, particularly the open ocean, present a fascinating exception. Here the pyramid of biomass is typically inverted, meaning the biomass of producers is actually less than that of consumers at higher trophic levels. This seems to violate basic ecological logic — how can a smaller base support a larger structure?
The answer lies in the nature of phytoplankton, the primary producers of marine ecosystems. These microscopic organisms have an extraordinarily high rate of reproduction and turnover. A single phytoplankton cell might live only a few days, but during that time it reproduces rapidly. So while the standing biomass of phytoplankton at any given moment is small, their productivity — the rate at which they produce new biomass — is enormous.
NoteThink of it like a busy restaurant with a small kitchen but very fast service. At any moment there aren't many dishes ready (small standing crop), but over the course of a day, hundreds of meals are produced (high productivity). …
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