Green Skills

Correct answer: B. Garden irrigation

Greywater is wastewater from relatively light domestic uses, such as handwashing, bathing, or laundry, and it is different from toilet sewage. The governing concept is safe water reuse: greywater must be kept separate from drinking water and used only when local guidance, treatment, and hygiene conditions make the reuse appropriate. Garden irrigation is a common suitable example, especially for ornamental plants and with care to avoid contamination of edible parts. Therefore, option B is correct. Drinking it directly is unsafe, throwing it into an open drain wastes water and may pollute surroundings, and spraying it in a classroom creates hygiene and health risks. Proper handling remains essential.

Correct answer: C. Conservation of water and land

A watershed is an area of land in which rainwater and surface runoff drain toward a common stream, lake, or other outlet. The governing concept of watershed management is coordinated conservation of water, soil, vegetation, and land use within that drainage area. Activities may include rainwater harvesting, checking soil erosion, restoring vegetation, protecting streams, and improving the use of available water. Therefore, option C, conservation of water and land, is correct. Water harvesting by itself is only one possible activity, while mobile games, classroom decoration, and increasing sound have no connection with managing a natural drainage area. The approach links land treatment with long-term water security.

Correct answer: C. Organic waste is usefully recycled and the soil receives nutrients

Compost is produced when microorganisms break down biodegradable materials such as leaves, grass, and suitable kitchen scraps under controlled conditions. The governing concept is circular use of organic matter: waste that might otherwise be discarded is returned to the soil as humus and plant nutrients. Compost can improve soil structure, support useful organisms, increase fertility, and help the soil retain moisture. Therefore, option C is correct because it combines useful recycling with soil nourishment. Options A and B describe the opposite of the usual benefit, while option D is not a normal effect of clean, properly prepared compost. Compost should still be made from safe materials and used appropriately.

Correct answer: A. Raising awareness about environmental conservation and encouraging participation in green activities

An eco club is a school-based group that develops environmental awareness and turns that awareness into practical participation. Its governing concept is collective action for sustainability. Members may conduct tree planting, cleanliness drives, waste segregation, composting, water conservation, energy-saving campaigns, biodiversity activities, and awareness programmes for the wider school community. Therefore, option A is correct because it includes both learning and participation in green activities. Option B is too narrow because an eco club is not only an entertainment group. Option C describes poor waste management, and option D conflicts directly with conservation. The purpose is responsible behaviour, not simply discussion.

Correct answer: B. Resource use and waste

An environmental audit is a systematic review of how an organisation, school, building, or activity affects and uses natural resources. The governing concept is measurement for environmental improvement. An audit can examine water consumption, electricity and fuel use, waste generation, segregation practices, paper use, pollution risks, and opportunities for conservation. Therefore, option B, resource use and waste, is correct. Student height, book colour, and a chair’s name are not indicators of environmental performance and do not help identify ecological impacts. The audit is useful because measured information can guide practical action, such as repairing leaks, reducing unnecessary energy use, improving recycling, and setting realistic conservation targets.

Correct answer: A. Analysing energy consumption and reducing wastage

An energy audit is a structured examination of where, when, and how energy is consumed in a building, institution, machine, or process. Its governing concept is energy efficiency: first measure or estimate consumption, then locate avoidable losses and recommend practical improvements. These may include switching off idle equipment, improving lighting, maintaining appliances, reducing leakage, and selecting efficient devices. Therefore, option A is correct because analysing consumption is used to reduce wastage. Options B and C deliberately increase consumption rather than improve efficiency. Option D concerns water maintenance and is unrelated to the primary purpose of an energy audit, although good facility management may address both areas separately.

Correct answer: A. Sources, consumption, and wastage of water

A water audit is a systematic assessment of the movement and use of water in a building, school, farm, organisation, or defined area. The governing concept is water efficiency through evidence-based checking. It normally considers the sources of water, quantities consumed, major uses, leaks, losses, wastewater, and possible conservation or reuse measures. Therefore, option A is correct because it identifies the sources, consumption, and wastage that an audit is designed to examine. Checking leaks is important but represents only one part of the wider review. Wall colour, classroom-bell maintenance, and computer-password security may matter for other purposes, but they do not measure water management or water efficiency.

Correct answer: A. Farming while conserving soil and water

Sustainable agriculture aims to produce food and support livelihoods while protecting the natural resources needed by future generations. Its governing concept is balance between agricultural production, environmental conservation, and long-term economic and social well-being. In practice, this may involve conserving soil and water, using nutrients carefully, reducing harmful pollution, protecting beneficial organisms, choosing suitable crops, and using efficient irrigation. Therefore, option A is correct because it states the essential idea of farming while conserving soil and water. Options B, C, and D describe degradation, waste, or harmful practice; they reduce future productivity rather than sustain it. Sustainability means meeting present needs without destroying the resource base.

Correct answer: B. Compost

A natural fertilizer is an organic material that supplies nutrients or improves soil condition without being manufactured as a synthetic chemical fertilizer. Compost is made by the controlled decomposition of biodegradable materials such as leaves, plant residues, and suitable kitchen waste. It contributes humus and nutrients, supports soil organisms, and can improve moisture retention and soil structure. Therefore, option B, compost, is correct. A chemical fertilizer may provide plant nutrients, but it is classified as synthetic rather than natural. Diesel is a fuel, not a fertilizer, and plastic powder is neither a safe nutrient source nor an appropriate soil amendment. The key distinction is between decomposed organic matter and industrial fuel or synthetic products.

Correct answer: C. Reducing the use of single-use plastic

The governing concept is the waste hierarchy, which gives priority to reducing waste before reusing or recycling it. Single-use plastic bags, straws, cups, and wrappers are often used briefly but remain in the environment for a long time. Choosing cloth bags, refillable bottles, and reusable containers directly prevents some plastic waste from being created. Burning plastic is unsafe because it may release harmful fumes, while dumping it on roads or in rivers pollutes land and water and can injure animals. Therefore, option C is correct because reducing unnecessary single-use plastic addresses the problem at its source.

Correct answer: A. Plastic that is generally used once and then discarded

Single-use plastic means a plastic product intended or commonly used for one short period before being discarded. Examples include thin carry bags, disposable cups, straws, cutlery, and some food wrappers. The important identifying feature is not merely that the item is made of plastic, but that it is normally thrown away after one use rather than being designed for repeated use. Option B describes durable reusable plastic, whereas ordinary plastic does not automatically become compost or dissolve in water, as suggested by options C and D. Thus option A gives the correct definition.

Correct answer: A. Using a dustbin

The governing concept is responsible waste disposal. A dustbin provides a designated place for collecting waste so that it can be transported, segregated, recycled, composted, or safely treated. Using one prevents litter from blocking drains, spreading germs, harming animals, and making public spaces unpleasant. Spreading waste on the road is littering, and throwing it into a river transfers pollution to water rather than solving it. Burning mixed waste can produce smoke and harmful pollutants, especially when plastics or other treated materials are present. Therefore, option A is the only responsible action among the choices.

Correct answer: B. Separating waste at the place where it is generated

Source segregation means separating waste at the point where it is produced, before different types become mixed. For example, a household, classroom, or office can place wet biodegradable waste, dry recyclable waste, and hazardous items in separate containers. This practice improves the quality of recyclables, supports composting, reduces contamination, and makes later treatment safer and more efficient. Dumping, burning, or mixing waste does not represent source segregation; in fact, mixing makes recovery more difficult. Therefore, option B is correct because it states both the timing and the location of the process.

Correct answer: B. Recycling paper

The direct answer is B: recycling paper. Recycling means collecting a used material, processing it, and using the processed material to make a new product or raw material. In paper recycling, old paper may be sorted, mixed with water to form pulp, cleaned, and processed into fresh paper products. Reuse is different: it means using the same sheet again without changing it into a new material, such as writing on its blank side or using it for rough work. Option C is wrong because decomposition is the natural breakdown of material by biological or chemical processes; it does not specifically mean making new paper. Option D is wrong because burning destroys the paper and may release smoke and pollutants. Thus the transformation of old paper into new paper is recycling. Memory cue: same object again is reuse; changed into a new product is recycling.

Correct answer: D. Printing double-sided when needed

Eco-printing applies resource-efficiency principles to printing. Printing on both sides of a sheet, when the document and printer permit it, can reduce the number of sheets required for the same amount of information. It therefore saves paper, lowers demand for fibre and production energy, and can reduce waste. A blank page does not provide a useful conservation action, using a new sheet for one line is wasteful, and operating a printer without need consumes electricity and supplies. The correct choice is option D, because duplex printing uses the available paper more efficiently while still meeting a genuine printing need.

Correct answer: A. The number of vehicles on the road and fuel use per person can decrease

Carpooling is shared travel in which two or more people use one vehicle for a similar journey. If several passengers who would otherwise travel separately share a car, the number of vehicles on the road can fall. Fuel use and exhaust emissions are then distributed across more passengers, so fuel consumption and emissions per person may decrease. The exact saving depends on distance, occupancy, vehicle type, and whether the shared trip replaces separate trips, but the general environmental benefit remains. Options B, C, and D describe outcomes opposite to the normal purpose of carpooling. Hence option A is correct.

Correct answer: B. It does not require vehicle fuel

Walking is a form of active, non-motorised transport. For a nearby journey, it does not require petrol, diesel, or electricity used by a motor vehicle, and it produces no direct vehicle exhaust at the point of travel. Replacing a short motorised trip with walking can therefore save fuel, reduce traffic-related emissions, and lower noise. The environmental benefit is strongest when walking actually replaces a vehicle journey; it is not necessary to claim that every trip has identical effects. Options A, C, and D incorrectly attribute fuel use or exhaust to walking. Thus option B is correct.

Correct answer: C. To protect the environment and health from harmful substances

Old batteries are a form of potentially hazardous waste. Depending on their chemistry, they may contain substances such as lead, mercury, cadmium, corrosive electrolytes, or other materials that can harm people and ecosystems if released improperly. Throwing batteries into ordinary rubbish or burying them can allow leakage into soil and water, while burning them can create dangerous fumes or residues. The responsible practice is to keep them separate and deliver them to an authorised collection, take-back, or e-waste recycling facility according to local rules. Therefore, option C states the reason for proper disposal.

Correct answer: D. Reuse

The principle of reuse means extending the useful life of an existing item by using it again without first converting its material into a new product. If a working phone, computer, tablet, or other electronic device is donated, another person can use that same device. This delays disposal, reduces demand for a new device, and can prevent e-waste from being generated immediately. Recycling is different because the device is dismantled or processed to recover materials. Repair may be needed before donation, but it is an action rather than the main principle described. Therefore, option D is correct.

Correct answer: A. Resource conservation

The governing concept is sustainable consumption, which means meeting needs while using fewer resources and creating less waste. Repairing an item keeps the existing product in use for a longer time. As a result, fewer raw materials, manufacturing processes, packaging materials, and units of energy are needed to produce a replacement. This directly conserves resources and usually reduces waste. Option B describes buying or using more than necessary, while options C and D are harmful environmental outcomes rather than benefits of repair. Therefore, option A is correct. Repair, reuse, and maintenance are practical green habits that support the circular use of products.

Correct answer: B. Plastic and waste

The governing concept is reuse and waste prevention. A refill pen has a durable outer body that remains in use, while only the empty ink refill is replaced. If a person buys a completely new disposable pen every time the ink ends, more plastic bodies, packaging, and discarded parts may be produced. Replacing only the refill can therefore reduce the amount of plastic used and the quantity of solid waste generated, although the exact saving depends on the product and how it is used. Study and knowledge are not reduced by the pen, and tree shade has no relevant connection. Thus, option B is correct.

Correct answer: C. Allowing rainwater to soak into the ground

The governing concept is sustainable stormwater management. A rain garden is a shallow, planted depression designed to receive rainwater from roofs, driveways, or other hard surfaces. Plants, roots, and soil slow the movement of water and allow part of it to infiltrate into the ground. This can reduce surface runoff, erosion, and local waterlogging, while also supporting groundwater recharge where soil and site conditions are suitable. It does not function by increasing air pollution, producing plastic waste, or increasing electricity use. Therefore, option C is correct. The result may vary with soil, rainfall, maintenance, and design, but infiltration is the intended basic function.

Correct answer: A. Clean electricity can be generated from sunlight for the home

The governing concept is renewable energy conversion. Photovoltaic cells in rooftop solar panels convert light energy from the Sun into electrical energy. The electricity can supply some household demand, and a grid-connected system may export excess generation according to local rules. Because sunlight is renewable and operation does not require burning coal or petroleum, solar power can reduce dependence on fossil-fuel-based electricity and associated emissions, although manufacturing, installation, storage, and grid conditions also have environmental considerations. Option A states the real benefit. Options B and C describe contrary effects, and option D is scientifically incorrect because sunlight is not directly converted into petroleum.

Correct answer: A. Energy and resource efficiency

The governing concept is resource-efficient and environmentally responsible building design. A green building aims to provide safe and useful indoor spaces while reducing unnecessary consumption of energy, water, materials, and other resources. Features may include efficient lighting and appliances, natural daylight, ventilation, water-saving fittings, durable or recycled materials, waste management, and designs that suit the local climate. The exact features vary by building and standard, but the central focus is efficiency and reduced environmental impact. Option A is therefore correct. More wastage and more smoke conflict with green design, while tall walls alone do not make a building environmentally sustainable or energy efficient.

Correct answer: B. It reduces the need for electricity

The governing concept is energy conservation through passive building design. During daylight hours, windows, skylights, and other openings can provide sufficient natural illumination for many indoor activities. When natural light is used effectively, people need to switch on fewer electric lamps or use them for fewer hours. This reduces the demand for electricity used for lighting, though the actual saving depends on the room, season, weather, window design, and user habits. Natural light does not inherently increase water use or dust, and increasing electricity consumption is the opposite of the expected benefit. Therefore, option B is correct and represents a common green-building practice.