Final answer:
Apical meristematic tissue is present at the tips of stems and roots, which is true, and is responsible for the primary elongation of these plant parts.
Step-by-step explanation:
The statement that apical meristematic tissue is present at the tips of stems and roots is true. The apical meristem is a region of actively dividing cells that are undifferentiated and found at the growing tips of the plant's shoots and roots. This tissue is responsible for the primary growth that allows the plant to extend in length. In stems, the apical meristem promotes vertical growth, enabling the plant to reach for light, while in roots, it allows the plant to push further into the soil to access water and nutrients. Additionally, apical meristems can become dominant in a single branch, leading to a more robust central trunk in many plant species.
While the apical meristem is instrumental in elongation, lateral meristems facilitate growth in the thickness or girth of the plant. Conversely, intercalary meristems only found in monocots, located at the base of the leaves or at nodes, allow leaves to grow longer, which is particularly noticeable in grasses that still elongate after being mowed.