Final answer:
Intermediate filaments are crucial for forming the nuclear lamina, providing structural support by resisting tension and anchoring organelles within the cell.
Step-by-step explanation:
The type of cytoskeletal fiber important in the formation of the nuclear lamina is intermediate filaments. These filaments are made up of fibrous proteins such as lamins (specifically the protein lamin that makes up the nuclear lamina), vimentin, and keratin. They serve various structural functions within the cell, including maintaining cell shape by resisting tension, anchoring organelles, and forming cell-to-cell junctions like desmosomes. Intermediate filaments are notable for their durability compared to other cytoskeletal structures such as microfilaments and microtubules, which can disassemble and reform rapidly.