Final answer:
The inspector should indeed inspect for combustible lintels above fireplace openings as they can pose a fire hazard. Non-combustible materials should be used instead. Also, it is true that lightning can travel through a tree to reach Earth, despite wood generally being an insulator.
Step-by-step explanation:
The statement that the inspector should inspect for combustible lintels above fireplace openings speaks directly to safety practices within building construction and relates to engineering principles. In the context of fireplaces, a lintel is a horizontal support across the top of the fireplace opening and is crucial for maintaining the structure of the chimney and surrounding wall. Combustible materials, such as some types of wood, are not recommended for use as lintels above fireplace openings because they can ignite due to being exposed to intense heat. Instead, non-combustible materials such as metal or certain types of stone are typically used. It is crucial that an inspector verify that the correct materials are used to prevent fire hazards.
Regarding the statement about lightning traveling through a tree, it's true that wood can conduct electricity, especially when it's wet, acting as a pathway for lightning to reach the ground. Despite wood being generally an insulator, the immense power of a lightning strike can overwhelm the resistive properties of wood, causing it to conduct the electrical charge to Earth.