67. What is earthquake engineering and its significance? (3 marks) 68. Describe the principles of seismic design. (3 marks) 69. What are the different types of construction materials used in earthquake-resistant structures? (3 marks) 70. Explain the concept of retrofitting in civil engineering. (3 marks) 71. What is the role of geosynthetics in civil engineering? (3 marks) 72. Describe the process of tunnel construction. (3 marks) 73. What is the significance of bridge engineering? (3 marks)