BECE 2006 Integrated Science Objective Questions and Answers

Solution: Water is a liquid that takes the shape of its container, while a rock (solid) maintains a fixed shape regardless of its container.

Solution: Opaque materials do not allow light to pass through. Mirrors are opaque because they reflect nearly all incident light.

Solution: Wood's low thermal conductivity prevents heat transfer from the hot utensil to the hand, reducing burns.

Solution: Warm air rises due to convection, so upper vents facilitate hot-air escape and cool-air intake below.

Solution: Like magnetic poles (north-north or south-south) repel each other according to fundamental magnetic laws.

Solution: Fuses contain a wire that melts during overcurrent, breaking the circuit to prevent appliance damage.

Solution: Angle of incidence is measured from the normal. Here, 90° - 20° = 70° is the angle of incidence, and reflection equals incidence.

Solution: A screw's threads act as a spiraled inclined plane, converting rotational force into linear motion.

Solution: Power (watts) = energy (joules) / time (seconds), making it the rate of energy consumption.

Solution: Forceps are third-class levers where effort (applied at the middle) lies between fulcrum (end) and load (tips).

Solution: Lubrication reduces friction between moving parts, minimizing energy loss and wear.

Solution: The plumule is the embryonic shoot that develops into the stem and leaves after germination.

Solution: Poliomyelitis (polio) is caused by a virus that attacks motor neurons in the spinal cord.

Solution: Cellular respiration breaks down glucose to release ATP (energy) in cells.

Solution: Decomposers (e.g., bacteria) break down dead matter, recycling minerals like nitrogen and phosphorus into the soil.

Solution: Concave lenses diverge light rays, correcting myopia (short-sightedness) by focusing light onto the retina.

Solution: Lungs expel CO₂ (a respiratory waste product) during exhalation.

Solution: Maize stems lack nodes/buds needed for vegetative propagation; maize is grown from seeds or cobs.

Solution: Washing soda (sodium carbonate) removes calcium/magnesium ions, converting hard water to soft water.

Solution: Soft water lacks Ca²⁺/Mg²⁺ ions, allowing soap to lather easily with minimal quantity.

Solution: Solar evaporation of seawater leaves behind salt crystals in salt pans.

Solution: Formulas like H₂SO₄ show elemental ratios (2H:1S:4O), not bonding or molecular count.

Solution: Turpentine (organic solvent) dissolves nonpolar grease, unlike water or palm oil.

Solution: H₂SO₄ contains hydrogen (H), sulfur (S), and oxygen (O) — three distinct elements.

Solution: Producers (autotrophs) synthesize food via photosynthesis, forming the base of food chains.

Solution: Plasmodium (transmitted by mosquitoes) causes malaria, characterized by fever and chills.

Solution: Vaccines stimulate white blood cells to produce antibodies, providing adaptive immunity.

Solution: Burning destroys organic matter and nutrients (like nitrogen), reducing soil fertility.

Solution: Stratus clouds form below 2,000 meters, often appearing as low-lying gray sheets.

Solution: Humidity quantifies atmospheric water vapor, affecting weather and comfort.

Solution: Pluto (dwarf planet) has the largest orbital radius in the solar system, ~39.5 AU from the Sun.

Solution: Rusting (iron oxidation) requires oxygen (\(4Fe + 3O_2 + 6H_2O \rightarrow 4Fe(OH)_3\)).

Solution: Noble metals (e.g., gold) resist oxidation, retaining a shiny surface unlike reactive metals that tarnish.

Solution: Ductility allows metals to be stretched into wires without breaking (e.g., copper wiring).

Solution: Processing (e.g., canning, drying) primarily extends shelf life by inhibiting microbial growth.

Solution: Capillary action draws liquid up narrow tubes (like wick fibers) against gravity via adhesion/cohesion.

Solution: Friction opposes motion (reducing speed), generates heat, and causes wear; it never increases speed.

Solution: Arteries carry oxygenated blood from the heart to tissues (except pulmonary artery).

Solution: Muscles facilitate movement but aren't part of the circulatory system (heart pumps, vessels transport).

Solution: Density = mass/volume → volume = mass/density = 10 kg / 2 kg/m³ = 5 m³.