Here are the solutions to your questions: 48. a) Organism B (octopus) belongs to the group Mollusca. b) Part K (shell) on organism C (snail) provides protection and support for the soft body. c) Organism A (crab) belongs to the group Arthropoda. Other organisms in this group include insects (e.g., grasshoppers) and spiders. d) The above organisms (crab, octopus, snail) are similar because they are all invertebrates, meaning they lack a backbone. 49. The table shows types of movable joints and their location in the human body: • Gliding joint: Wrists and ankle • Pivot joint: Neck • Hinge joint: Elbows and knees • Ball and socket joints: Shoulder 50. a) Two reasons why electricity is a form of energy: i) It can be converted into other forms of energy, such as light (in a bulb), heat (in a heater), or mechanical energy (in a motor). ii) It can do work, for example, powering appliances to perform tasks. b) Two reasons why the use of electricity is environmentally friendly: i) It helps to reduce the rate of deforestation by providing an alternative to burning wood for energy. ii) When generated from renewable sources (like solar or wind), its use does not directly produce greenhouse gases or pollutants at the point of consumption. 51. a) Apart from egg eating, another vice in poultry is vent pecking. b) One cause of egg eating is a lack of calcium in the diet.