Which asbestos type is known for its straight fibers?

The type of asbestos known for its straight fibers is Amphibole. Amphibole asbestos includes types like amosite and crocidolite, which are characterized by their needle-like, straight fibers. This structure contributes to the unique properties of Amphibole, making it more durable and heat-resistant compared to other asbestos types.

In contrast, Serpentine asbestos fibers, such as chrysotile, are curly or wave-like in structure. While chrysotile is a significant form of asbestos commonly encountered, the fiber shape does not match the straight fiber characteristic attributed to Amphibole asbestos. Polyester is not an asbestos type at all and is unrelated to the properties or classification of asbestos fibers. Therefore, Amphibole stands out as the correct answer due to its distinct fiber structure.