Most mechanical splices incorporate a sleeve or collar that aligns the fiber ends and secures them with _____.

The correct choice indicates that most mechanical splices use both adhesive and pressure to secure the fiber ends and ensure proper alignment. This dual approach enhances the splice’s reliability and performance. The pressure helps maintain contact between the fiber ends, which is crucial for effective light transmission, while the adhesive fills any microscopic gaps and bonds the fibers together to minimize losses and maintain a stable connection.

In mechanical splicing, precise alignment of the fiber cores is essential for optimal signal transfer, making the combination of pressure and adhesive particularly effective in achieving a durable and effective splice. The other methods listed, such as glue only, pressure only, or heat only, do not provide the same level of reliability and effectiveness, as they lack the complementary benefits of using both adhesive and pressure together.