Describe three excretory products, two excretory organs, the purpose and benefits of grafting in crop production, and two reasons for using scientific methods, with one reason for specific laboratory

Hey Desmond, good to see you again. 1. a) (i) Three substances excreted from the human body: • Urea • Carbon dioxide • Water (as sweat or urine) (ii) Two organs in humans which perform excretory function: • Kidneys • Lungs (or Skin) b) (i) Grafting is used in crop production to join parts of two plants (a scion and a rootstock) so that they grow as a single plant, combining desirable characteristics from both. (ii) Three benefits of grafting: • It allows for the propagation of desirable varieties that may not grow well from seeds or cuttings. • It can confer disease resistance or pest resistance from the rootstock to the scion. • It can lead to earlier fruiting or improved fruit quality. c) (i) Two ways in which scientific methods are important: • They provide a systematic and logical approach to investigate natural phenomena and acquire new knowledge. • They enable the development of new technologies and solutions to practical problems. (ii) One reason for each laboratory rule: (α) Do not wear rubber slippers to the laboratory: To protect feet from chemical spills, broken glass, or electrical shocks. (β) Close all taps before leaving the laboratory: To prevent flooding and conserve water. (γ) Spilled liquids must be cleaned immediately: To prevent slips and falls, and to avoid contamination or damage to equipment/surfaces. d) (i) Earthing in household wiring is a safety measure that connects the metal casing of electrical appliances to the ground via a low-resistance wire. This provides a safe path for fault current to flow directly to the earth in case of an electrical fault, preventing electric shock. (ii) Two sources of electric power generation: • Hydroelectric power • Thermal power (e.g., coal, natural gas) 2. a) Four reasons why farmers should be discouraged from using chemical fertilizers: • Eutrophication: Runoff of excess fertilizers into water bodies can lead to algal blooms, depleting oxygen and harming aquatic life. • Soil acidification: Prolonged use can alter soil pH, making it unsuitable for certain crops and harming beneficial soil microorganisms. • Chemical runoff: Fertilizers can leach into groundwater, contaminating drinking water sources. • Harm to beneficial organisms: High concentrations can be toxic to earthworms and other beneficial soil organisms. b) (i) Temporary hard water is water that contains dissolved hydrogen carbonates of calcium and magnesium. It can be softened by boiling, which precipitates the calcium and magnesium carbonates. (ii) Chemical equation to show how temporary hard water can be softened by heating: Ca(HCO_3)_2(aq) heat CaCO_3(s) + H_2O(l) + CO_2(g) c) (i) A lever is a simple machine consisting of a rigid bar that pivots around a fixed point called a fulcrum, used to multiply force or change the direction of force. (ii) Explanation of terms as applied to simple machines: (α) Mechanical advantage: It is the ratio of the load (resistance force) to the effort (applied force). A mechanical advantage greater than 1 means the machine multiplies the applied force. (β) Velocity ratio: It is the ratio of the distance moved by the effort to the distance moved by the load in the same amount of time. It is a theoretical value determined by the machine's design. d) (i) Food processing is the transformation of raw agricultural products into food, or of food into other forms, for consumption by humans or animals. It involves various physical and chemical methods. (ii) State: (α) Two advantages of food processing: • Preservation: It extends the shelf life of food, reducing spoilage and waste. • Convenience: It makes food easier and quicker to prepare and consume. (β) One disadvantage of food processing: • Loss of nutrients: Some processing methods can reduce the nutritional content (e.g., vitamins) of food. Drop the next question.