Final answer:
True, leaks in a vehicle's fuel system can occur from both the fuel lines and the tank, with thermal expansion playing a significant role.
Step-by-step explanation:
True, leaks in the fuel system can occur in the fuel lines or from the tank. This is because both the fuel lines and the tank are integral parts of a vehicle's fuel system, which is designed to store and deliver fuel to the engine. The concept of thermal expansion plays a role in understanding how these leaks can happen. For instance, when gasoline is pumped into a vehicle's tank, it may be cooler than the ambient air temperature. As the gasoline warms up to match the surrounding air temperature, it expands much more significantly than the steel of the tank due to thermal expansion. If a tank is filled completely on a hot day, this expansion can lead to gasoline overflowing. Therefore, it is crucial to consider the thermal properties of materials when designing and maintaining fuel systems to prevent leaks.