Final answer:
The statement that "all plants can be propagated by sexual propagation" is b)false because many plants employ asexual reproduction methods as well, resulting in genetically identical offspring to the parent plant.
Step-by-step explanation:
While sexual propagation is indeed widespread among plants, it's not the only method they use. Many plants are capable of asexual reproduction, where they can produce genetically identical offspring without the involvement of male and female gametes.
Asexual reproduction can be advantageous in stable environmental conditions, as the offspring will be exactly like the parent, preserving successful genetic traits. Plants can employ various methods of asexual reproduction such as grafting, layering, cuttings, and natural methods like runners or rhizomes. Therefore, while many plants can reproduce sexually, they do not exclusively rely on this method and can also propagate asexually. So the answer is option b.