Home Science (Theory) | Code 71/SS/321 Set A1

Correct Answer: (A) Refrigerator

Detailed Explanation: A domestic refrigerator maintains a controlled low temperature between 1 °C and 5 °C. This low temperature significantly retards bacterial multiplication and inhibits endogenous enzymatic reactions without solidifying cooked dishes, making it ideal for the safe, short-term storage (24 to 72 hours) of cooked curries, boiled milk, and leftovers. In contrast, a Freezer operates below 0 °C (used for long-term frozen food preservation), while a Grameen Sheetal (evaporative pot-in-pot cooler) is suitable primarily for raw fruits and vegetables, not perishable cooked dishes.

Correct Answer: (C) (i) and (iii)

Detailed Explanation: The core scientific principles governing food preservation are: 1. Destruction of spoilage micro-organisms through thermal processing, pasteurization, or radiation (statement i). 2. Inactivation of food enzymes through blanching and heating (statement iii). 3. Removal or reduction of moisture (dehydration, osmophilic concentration with sugar/salt), because moisture supports microbial growth; therefore, increasing moisture (statement iv) induces spoilage rather than preventing it.

Correct Answer: (B) Nutritional status

Detailed Explanation: Nutritional status is defined as the physiological condition of an individual resulting from the relationship between dietary nutrient intake, absorption, internal assimilation, and cellular metabolic requirements. It can be assessed using anthropometry, biochemical tests, clinical signs, and dietary surveys. If this status is impaired, it manifests as malnutrition (either undernutrition or overnutrition).

Correct Answer: (C) (i) and (iii)

Detailed Explanation: Keeping financial accounts provides accurate visibility into where family funds are going, helps identify wasteful or unplanned expenses, and enables month-to-month comparative evaluation to refine the household budget and boost savings. It does not provide a guarantee of increased income, nor does it encourage undisciplined spending.

Correct Answer: (B) Peer Group Culture

Detailed Explanation: Peer group culture consists of the shared subcultural codes, slang, musical tastes, grooming habits, and clothing styles developed by adolescents to establish mutual belonging, social solidarity, and emotional autonomy from adult authority.

Correct Answer: (B) Dead Storage

Detailed Explanation: Dead storage refers to designated areas (such as high lofts, overhead kitchen cupboards, attic shelves, or under-bed trunks) used for storing articles required only occasionally (e.g., seasonal quilts, travel suitcases, festival decorations). In contrast, live or active storage is reserved for everyday articles kept within comfortable reach.

Correct Answer: (C) 28

Detailed Explanation: By the close of middle childhood (~12 years of age), all 20 primary (milk) teeth are shed and replaced by 28 permanent teeth (8 incisors, 4 canines, 8 premolars, and 8 molars). The remaining 4 molars (wisdom teeth) typically erupt later, between 17 and 25 years of age, completing the full adult set of 32.

Correct Answer: (A) Includes foods from diverse groups, combining plant and animal sources

Detailed Explanation: A balanced diet contains adequate proportions of carbohydrates, proteins, fats, vitamins, minerals, water, and roughage. Incorporating both plant sources (cereals, pulses, green vegetables) and animal/dairy products ensures mutual amino acid supplementation (e.g., cereals deficient in lysine combined with pulses deficient in methionine) and high bioavailability of micronutrients like vitamin B12, iron, and calcium.

Correct Answer: (C) Conservation

Detailed Explanation: According to Jean Piaget's cognitive theory, conservation is the ability to understand that fundamental physical properties (such as volume, mass, or number) remain identical despite perceptual transformations in container shape. Children develop this during the Concrete Operational Stage (ages 7 to 11), overcoming the pre-operational error of centration.

Correct Answer: (B) Marasmus

Detailed Explanation: Marasmus is a severe manifestation of Protein-Energy Malnutrition (PEM) caused by a combined deficiency of total calories and protein. The body catabolizes its own muscle and subcutaneous adipose tissue, producing a withered look, prominent ribs, loose folded skin ("baggy pants" sign), and a shrunken abdomen. By contrast, Kwashiorkor (pure protein deficiency with adequate carbohydrates) is marked by edema (swelling of feet and hands), moon face, and a distended potbelly.

Correct Answer: (C) Silk

Detailed Explanation: Silk (as well as wool) is a natural protein fibre. In the presence of water, the hydrogen bonds between polypeptide chains weaken, resulting in a loss of approximately 15% to 20% of its tensile strength. Therefore, silk requires delicate handling, kneeling, and gentle squeezing rather than aggressive wringing. In sharp contrast, Cotton actually gains 10% to 20% tensile strength when wet due to increased internal crystallization and hydrogen bonding, allowing it to withstand vigorous scrubbing.

Correct Answer: (C) Shaking hands, hugging, or social kissing

Detailed Explanation: HIV is transmitted exclusively via exchange of specific body fluids: blood, semen, vaginal secretions, and breast milk (mother-to-child). It cannot survive outside the human body and is not spread through everyday social interactions like hugging, sharing food, sneezing, touching toilet seats, or mosquito bites.

Correct Answer: (B) To prevent colour bleeding, cross-staining, and fabric abrasion

Detailed Explanation: Sorting laundry by color (whites vs. coloreds), fabric delicacy (delicate silks and woolens vs. sturdy cottons), and degree of soiling ensures that fugitive dyes do not stain whites, heavy items do not abrade delicate weaves, and appropriate water temperatures and wash actions are chosen.

Correct Answer: (B) The float ball is punctured, cracked, or corroded, letting water inside

Detailed Explanation: The hollow floating ball operates a brass lever mechanism that closes the inlet valve once water reaches the set line. If the float ball is punctured or cracked, water seeps into its interior, destroying its buoyancy. The heavy ball sinks, failing to lift the lever arm, which leaves the inlet valve open and leads to continuous overflow into the toilet bowl.

Correct Answer: (B) It provides versatile support, holding stems securely at any desired angle

Detailed Explanation: Water-soaked floral foam ('Oasis') is light, pliable, and easily cut to fit any container shape. It holds thin or thick floral stems firmly at any 3-dimensional angle, preventing them from shifting or collapsing, whereas pin-holders require greater balancing skill and floral wire mechanics.

Correct Answer: (B) Prevent pest infestation, eliminate pathogens, and protect health

Detailed Explanation: Beyond aesthetic appeal, regular cleaning removes dust, food debris, greasy films, and moisture. These residues provide breeding grounds for pests (cockroaches, flies, rodents) and disease-causing pathogens (bacteria, fungi, allergens), protecting the physical health and safety of family members.

Correct Answer: (B) Naturalized

Detailed Explanation: Naturalized designs represent recognizable motifs drawn from real life—such as cute animals (rabbits, ducks), flowers, birds, and toys—in a realistic or pictorial form. Children readily identify with and enjoy these concrete, friendly shapes over complex geometric or abstract patterns.

Correct Answer: (B) Value

Detailed Explanation: Value describes how light or dark a color is. Adding white to a pure hue raises its value, producing a tint (e.g., pink), while adding black lowers its value, producing a shade (e.g., maroon). Hue is the pure name of the color family (e.g., red, blue), while intensity (chroma) measures its brightness or dullness.

Correct Answer: (C) Chain stitch

Detailed Explanation: Chain stitch is an outline or filling looped stitch. The needle emerges on the design line, the working thread forms a loop, and the needle is re-inserted into or adjacent to the original exit point, bringing the tip up a short distance ahead over the thread loop. This creates an interconnected chain-like pattern.

Four Work Ethics Identified: [1/2 × 4 = 2 Marks]

1. Punctuality and Regularity: Demonstrated by arriving ahead of time and respecting organizational commitments.
2. Courtesy and Professional Politeness: Demonstrated by respectful, polite interactions with peers and clients.
3. Safety Consciousness / Compliance: Adhering to laboratory safety norms to prevent accidents and protect health.
4. Confidentiality and Professional Integrity: Safely guarding proprietary information and maintaining organizational trust.

(i) Overnutrition / Nutritional Obesity: [1 Mark] Occurs when energy intake consistently exceeds the body's daily metabolic expenditure, leading to excessive lipid storage in adipose tissues.

(ii) Malnutrition: [1 Mark] An umbrella pathological condition encompassing undernutrition (wasting, stunting), micronutrient deficiencies, or overnutrition.

(i) False (F): [1/2 Mark] Biogas slurry is rich in nitrogen, phosphorus, and organic humus; it serves as safe, weed-seed-free organic manure.

(ii) True (T): [1/2 Mark] Light-colored walls possess a high reflection factor (albedo), maximizing natural daylight and ambient artificial light distribution.

(iii) False (F): [1/2 Mark] Box solar cookers provide gentle, indirect, and uniform heat; food does not burn or boil over, requiring zero stirring.

(iv) True (T): [1/2 Mark] Poor ergonomic design forces awkward postures and uneven muscle loading, elevating energy expenditure and accelerating fatigue.

Agent A: Optical Brightener / Fluorescent Whitening Agent (FWA) [1/2 Mark]

Agent B: Bluing Agent / Laundry Blue (Ultramarine Blue / Liquid Blue) [1/2 Mark]

Agent C: Enzyme Detergent / Enzymatic Stain Remover (Protease/Amylase) [1/2 Mark]

Agent D: Starching Agent / Laundry Starch (Rice or Corn Starch) [1/2 Mark]

Four Highly Liquid Investment Schemes: [1/2 × 4 = 2 Marks]

1. Savings Bank Account (SB A/c): Instant cash access anytime via ATM cards, cheques, UPI, and online banking.
2. Post Office Savings Account: Government-backed savings account allowing on-demand cash withdrawal at any post office counter.
3. Liquid Mutual Funds / Overnight Funds: Short-term debt instruments that permit redemption within 24 hours without significant exit penalties.
4. Flexi-Fixed Deposit / Sweep-in FD: Automatic link between savings account and term deposits providing liquidity during emergency fund shortages.

(i) Satin Stitch: [1 Mark] A solid flat filling stitch used to fill small floral petals, leaves, and geometric motifs, yielding a smooth, lustrous, satin-like surface.

(ii) Herringbone Stitch: [1 Mark] A versatile border and hem-finishing stitch used for decorative bands, filling foliage, and creating shadow work on sheer fabrics (like organdy or chiffon).

Scientific Steps for Freezing Fresh Peas: [2 Marks]

1. Shelling and Sorting: Select fresh, tender, bright green sweet garden peas. Discard hard, starchy, or damaged seeds and wash thoroughly in cold water. [1/2 Mark]
2. Blanching (Crucial Step): Immerse peas in rapidly boiling water for 1.5 to 2 minutes. Blanching inactivates enzymes (such as catalase and peroxidase) that otherwise cause tough skins, nutrient degradation, and off-flavors during freezing. [1/2 Mark]
3. Ice-Water Shocking: Transfer blanched peas immediately into ice-cold water (0 °C to 4 °C) for 2 minutes to halt the cooking process. [1/2 Mark]
4. Draining and Deep Freezing: Drain on clean towels, pack into moisture-vapor-proof polythene bags, expel excess air, seal airtight, and store in the deep freezer at -18 °C or below. [1/2 Mark]

Two Immediate Stain Removal Steps: [1 + 1 = 2 Marks]

1. Blot Immediately and Flush with Cold Water: Gently blot the greasy excess with a clean tissue or blunt scraper without rubbing (rubbing spreads turmeric pigment deeper into the fibers). Hold the reverse side under cold running water to push the curry particles outward. [1 Mark]
2. Apply Detergent and Sun Bleach (Avoid Alkaline Soap Initially): Rub a few drops of liquid detergent or paste of detergent powder onto the stain, rinse, and expose the wet fabric to direct sunlight. Natural sunlight photochemically bleaches turmeric (curcumin). Note: Avoid applying high-alkaline laundry soap bar directly onto fresh turmeric, as alkali reacts with curcumin to produce an indelible rust-red stain. [1 Mark]

Recommended Method: Aerobic Composting or Vermicomposting [1 Mark]

Layer biodegradable wet kitchen waste (vegetable peels, leftover food, fruit scraps) with dry leaves in a compost pit or compost bin with earthworms (Eisenia fetida).

Technical Reasons: [1 + 1 = 2 Marks]

1. Prevents Structural Damage to Flooring: Dripping water seeps into grout joints, unsealed floorboards, or tile seams, causing warping, adhesive failure, wood rot, or unsightly efflorescence marks.
2. Effective Soil Removal & Slip Hazard Prevention: A damp mop traps and lifts particulate dust through surface capillary tension, whereas a soaking mop merely sloshes muddy slurry around and leaves pools of water that pose slip-and-fall hazards and foster mold.

Reasons for Orderly Arrangement: [1 + 1 = 2 Marks]

1. Conservation of Time and Energy: Having a designated location for every item avoids frantic searches, reduces frustration, and streamlines daily household workflows.
2. Safety and Accident Reduction: Clutter-free floors, clear pathways, and properly positioned furniture prevent trips, collisions, and falls for children and elderly family members.

Purpose of Scaling Embroidery Designs: [1 + 1 = 2 Marks]

1. Maintaining Proportion and Harmony: Textiles come in varied dimensions (e.g., a handkerchief vs. a bedsheet border). Scaling ensures the motif fits the target area proportionally without looking crowded or lost.
2. Fabric and Thread Compatibility: Fine fabrics and delicate threads require smaller, detailed motifs, whereas heavier fabrics (canvas, linen) require enlarged outlines to accommodate thicker embroidery yarns.

Why Knots Should Be Avoided: [1 Mark]

Knots form unsightly, bulky lumps on the reverse side of the work that show through fine or sheer fabrics, interfere with smooth pressing/ironing, and can work loose during laundering, unraveling the stitches.

Correct Anchoring Methods: [1 Mark]

• Running / Backstitch Method: Take 2 to 3 tiny running stitches directly on the line of design that will be covered by the surface embroidery.
• Waste Knot Method: Tie a knot placed temporarily outside the design area, stitch over the thread tail on the reverse side, and snip away the waste knot flush with the fabric once secure.