$21.$ True or False: Ternary phase diagrams are only applicable to liquid$-$liquid extraction processes.

$22.$ True or False: Cross$-$current extraction is more efficient than counter$-$current extraction when dealing with very dilute solutions.

$23.$ True or False: The efficiency of an extraction process does not depend on the physical properties of the solvent.

$24.$ True or False: Batch extractors offer more flexibility in operation compared to continuous extractors.