In an introduction to the cytoskeleton, which statement correctly describes flagella in plant and animal cells?

• A. Flagella are present in all plant cells and all animal cells and are responsible for cytokinesis.
• B. Flagella are actin-based structures; they are common in plant cells but absent from animal cells.
• C. Flagella are composed primarily of intermediate filaments and are found in most plant and animal cells.
• D. Flagella are microtubule-based structures; they are common in some animal cells (e.g., sperm) but are absent from most plant somatic cells.

Answer: (D)