What is the main purpose of a pin in fastening systems?

The main purpose of a pin in fastening systems is to secure connections. Pins effectively hold components together, preventing them from separating under load or stress. In various applications, pins are utilized in mechanical assemblies to ensure that parts remain aligned and connected during operation, which is crucial for maintaining the integrity and functionality of the overall system.

While other choices may provide certain benefits, the primary function of a pin remains its role in securing connections. For instance, increasing strength (as suggested by one of the alternatives) is more of a result of the design or material of the assembly rather than the specific role of pins. Similarly, relieving tension or adjusting height might be considerations in a broader context of assembly adjustments but are not directly related to the fundamental purpose of a pin. Thus, securing connections stands as the most relevant answer in this context.