1. Kidney and urine regulation: Bowman’s capsule filtering structure, components excluded from filtrate (proteins, blood cells), glucose reabsorption, impact of ambient temperature on urine volume and production rate. 2. Respiratory system: nasal breathing advantages (mucus filtration, warming), tracheal cartilage support, bronchi identification, medulla oblongata controlling breathing, oxygen absorption calculation, carbon monoxide effect on haemoglobin. 3. Skin and thermoregulation: functions (protection, sensation), colour change after exercise due to increased blood flow for heat loss, sweating rate correlated with skin temperature, measurement using sweat collection or mass difference. 4. Immunity and disease: artificial immunity types (passive vs active), injection response analysis for disease treatment, natural immunity from infection via antibody production and memory cell formation. 5. Vision mechanisms: focusing on near vs distant objects (lens shape, muscle contraction, ligament tension), stereoscopic vision from image comparison in both eyes enabling depth perception, catching-ball experiment design. 6. Nervous vs hormonal systems: comparison of transmission method, signal type, response speed; synapse impulse directionality, neurotransmitter release, receptor-specific action, one-way impulse travel.