Final answer:
The false statement about lamellipodia is that they contain bundles of microtubules. Instead, they feature a branched network of actin filaments that are essential for membrane extension and cell motility.
Step-by-step explanation:
The statement that is false about lamellipodia is C) They contain bundles of microtubules that push the plasma membrane forward. Lamellipodia are known to contain branched networks of actin filaments, not microtubules, which are responsible for pushing the plasma membrane forward and play a critical role in cell motility, especially at the leading edge of crawling cells. Their formation is indeed stimulated by the activation of Rac, a small GTPase that is involved in the reorganization of the actin cytoskeleton. In addition, lamellipodia may have associated filopodia, which are finger-like protrusions also containing actin filaments that can explore the environment and contribute to cell motility.