BECE 2007 Integrated Science Objective Questions and Answers

Solution: All matter occupies space (volume) and has mass, but not all matter has a fixed shape (e.g., gases) or fixed density.

Solution: The bulb converts electrical energy from the battery into visible light energy, which is the primary output obtained.

Solution: Magnets only attract ferromagnetic materials (e.g., iron, steel). Glass is non-magnetic and unaffected.

Solution: Conduction involves direct transfer of heat through molecular collisions in solids, especially efficient in metals.

Solution: Thermometers specifically measure temperature via thermal expansion of liquids (e.g., mercury) or electronic sensors.

Solution: Refraction bends light rays at the water-air interface due to the change in light speed, causing visual distortion.

Solution: Opaque materials do not transmit light; mirrors reflect nearly all incident light, making them functionally opaque.

Solution: An inclined plane reduces effort by allowing gradual elevation change, ideal for rolling heavy drums upward.

Solution: The elbow acts as the fulcrum, effort is applied by biceps near the fulcrum, and resistance (e.g., weight) is at the hand—a third-class lever.

Solution: Enzymes catalyze the breakdown of complex food molecules (e.g., amylase for starch) during digestion.

Solution: Pepsin in gastric juice begins protein hydrolysis in the acidic environment of the stomach.

Solution: Reflex arcs bypass the brain; sensory neurons relay signals to the spinal cord, which directly triggers motor neurons.

Solution: Veins are blood vessels unrelated to the CNS, which comprises the brain and spinal cord only (nerves are peripheral).

Solution: Cotyledons (seed leaves) form the bulk of the seed, storing nutrients and becoming visible after testa removal.

Solution: Roots anchor plants via branching and root hairs, preventing displacement while absorbing water/minerals.

Solution: CSM is caused by viral (e.g., enteroviruses) or bacterial agents, but viral meningitis is common (cholera, TB, and malaria are bacterial/protozoan).

Solution: Teeth morphology (e.g., carnassials in carnivores, molars in herbivores) directly correlates with diet/feeding habits.

Solution: Gas exchange (O₂/CO₂) occurs in alveoli within the lungs, facilitated by capillaries and thin membranes.

Solution: Hard water contains Ca²⁺/Mg²⁺ ions that react with soap to form scum, reducing lathering efficiency.

Solution: Boiling kills pathogens (bacteria, viruses) effectively, unlike filtering (which may miss microbes) or chemical additives.

Solution: Crystallization uses cooling to reduce solute solubility, forming pure solid crystals from a saturated solution.

Solution: Charcoal is insoluble and denser than water, leading to sedimentation due to gravity over time.

Solution: Potassium's symbol is K (from Latin "kalium"), while Na is sodium, Pb is lead, and S is sulfur.

Solution: The atomic number (17) equals proton count; in a neutral atom, electrons equal protons (17).

Solution: Mulch (e.g., straw) reduces evaporation by shading soil and blocking wind exposure.

Solution: Erosion washes away mineral nutrients (N, P, K), degrading soil fertility for agriculture.

Solution: Fungal pathogens (e.g., Fusarium spp.) invade hooves/tissue, causing rot in livestock.

Solution: Cholera (Vibrio cholerae) causes severe watery diarrhea/vomiting; dysentery involves blood, influenza is respiratory.

Solution: Cement dust (air pollution), refuse dumping (water pollution), and burning rubbish (air/soil pollution) all harm the environment.

Solution: Scars are acquired physical traits, not encoded in DNA; eye color, nose shape, and height involve genetic inheritance.

Solution: The Sun contains 99.8% of the solar system's mass, with planets orbiting it gravitationally.

Solution: Heating NH₄Cl with Ca(OH)₂ produces ammonia gas: 2NH₄Cl + Ca(OH)₂ → CaCl₂ + 2NH₃ + 2H₂O.

Solution: Steel primarily combines iron with 0.1–2% carbon; brass is copper-zinc, and iron-zinc is galvanized coating.

Solution: Malleability allows metals to deform under compression (e.g., hammering) without breaking.

Solution: Diffusion describes spontaneous particle movement down a concentration gradient (e.g., perfume spreading in air).

Solution: Capillaries are thin-walled vessels enabling O₂ diffusion from blood to tissues via their extensive network.

Solution: Density = mass/volume. Volume = 2m × 2m × 2m = 8 m³. Density = 24 kg / 8 m³ = 3 kg/m³.

Solution: Friction acts parallel to surfaces in contact, resisting relative motion (e.g., sliding, rolling).

Solution: Surface tension creates a cohesive "skin" on water, resisting penetration through small openings.

Solution: Sun-drying evaporates moisture using solar heat, inhibiting microbial growth in foods like grains/fruits.