Final answer:
Meristematic tissue consists of meristems, which are responsible for a plant's continuous growth. Parenchyma cells, making up the cortex and pith, do not contribute to length increase but have other roles in the plant's physiology.
Step-by-step explanation:
Plant regions of continuous growth are comprised of meristematic tissue, containing cells that constantly divide and contribute to the growth of the plant. These regions are referred to as meristems. Specifically, parenchyma cells make up key portions of plant stems, including the cortex and pith. Unlike meristematic tissue, parenchyma cells typically do not divide and are involved in various functions like storage, secretion, and photosynthesis within the plant.
Meristem regions are responsible for primary growth in plants, leading to an increase in length. They are found at the tips of shoots and roots, known as the apical meristems. The overall plant growth process, from meristematic cells in meristems dividing and differentiating into various cell types, is a fundamental aspect of plant biology.