Outline the excretory functions in the human body and discuss grafting and laboratory safety rules.

Hey Mhiz — ready when you are. a) (i) Three substances excreted from the human body are: • Urine • Sweat • Carbon dioxide (ii) Two organs in humans which perform excretory function are: • Kidneys • Lungs b) (i) Grafting is used in crop production to join parts of two plants so that they grow as one plant. This allows combining desirable traits from different plants. (ii) Three benefits of grafting are: • It allows for the propagation of plants that do not root easily. • It can be used to combine desirable characteristics from two different plants (e.g., disease resistance from the rootstock and high yield from the scion). • It can be used to repair damaged plants or to change the variety of a fruit tree. c) (i) Two ways in which scientific methods are important are: • They provide a systematic approach to understanding the natural world and solving problems. • They lead to the development of new technologies and innovations that improve human life. (ii) One reason for each of the following laboratory rules: (α) Do not wear rubber slippers to the laboratory: • Rubber slippers offer inadequate protection against chemical spills or broken glassware. (β) Close all taps before leaving the laboratory: • To prevent water wastage and potential flooding. (γ) Spilled liquids must be cleaned immediately: • To prevent slips and falls, and to avoid contamination or damage to equipment/surfaces. d) (i) Earthing, as used in household wiring, is a safety measure that connects the metal casing of an electrical appliance to the ground. This provides a path for current to flow safely to the earth in case of a fault, preventing electric shock. (ii) Two sources of electric power generation are: • Hydroelectric power • Solar power a) Four reasons why farmers should be discouraged from using chemical fertilizers: • They can lead to soil degradation over time, reducing soil fertility and structure. • They can cause water pollution (eutrophication) when runoff enters rivers and lakes, harming aquatic ecosystems. • They can harm beneficial soil microorganisms and insects, disrupting the natural balance of the ecosystem. • They are often expensive and their production relies on non-renewable resources. b) (i) Temporary hard water is water that contains dissolved hydrogen carbonates (bicarbonates) of calcium and magnesium. It can be softened by boiling, which causes the bicarbonates to decompose and precipitate as insoluble 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. It is used to multiply force or change the direction of force. (ii) Explanation of terms as applied to simple machines: (α) Mechanical advantage: • The ratio of the output force (load) to the input force (effort). It indicates how much a machine multiplies the force applied to it. (β) Velocity ratio: • The ratio of the distance moved by the effort to the distance moved by the load. It indicates how much faster the effort moves compared to the load. d) (i) Food processing is any method used to transform raw ingredients into food or to transform food into other forms for consumption. This can involve various physical or chemical operations. (ii) (α) Two advantages of food processing: • Food preservation, which extends shelf life and reduces spoilage. • Increased convenience for consumers, as foods are often pre-prepared or ready-to-eat. (β) One disadvantage of food processing: • Potential loss of nutrients (e.g., vitamins) during processing. Send me the next one 📸