Microtubules Enable Key Cellular Movements and Structures

Steps:

• Identify microtubules as dynamic cytoskeletal filaments composed of tubulin.
• Verify function 1: Microtubules form axonemes in cilia, enabling beating motion for cell motility.
• Verify function 2: During metaphase, microtubules of the mitotic spindle attach to kinetochores at centromeres to align chromosomes.
• Verify function 3: Microtubules act as tracks for motor proteins like kinesin and dynein to transport secretory vesicles.

Why A is correct:

• Microtubules perform all three roles as integral cytoskeletal elements, per cell biology definitions of their structural and transport functions.

Why the others are wrong:

• B: Omits vesicle transport, a core microtubule duty via motor protein trafficking.
• C: Omits centromere attachment, vital for chromosome segregation in mitosis.
• D: Omits cilia movement, essential for microtubule-based motility in eukaryotic cells.

Final answer: A