Above the maturation region in a root, what type of tissue continues to grow as part of primary growth?

The correct answer identifies the type of tissue that is responsible for continued growth in a root as it undergoes primary growth. In plant biology, primary growth is the process responsible for the elongation of roots and shoots, allowing plants to grow taller and deeper. This growth occurs in the apical meristem located at the root tips and shoot tips.

Primary tissue refers specifically to the tissues that develop from the apical meristem and include protoderm, ground meristem, and procambium, which give rise to the epidermis, cortex, and vascular tissues respectively. Above the maturation region, the apical meristem is still actively dividing and contributing to primary growth, which means that the tissues formed from this meristem are considered primary tissues. This allows for the continuous elongation of the root.

In contrast, structures like the cortex and vascular cambium have specific functions and locations within the root structure—cortex is primarily involved in storage and transport, while vascular cambium contributes to secondary growth, not primary. The maturation region itself refers to the area where cells mature and differentiate, rather than where new growth occurs.

Thus, the recognition that primary tissue continues to be formed above the maturation region in response to the apical meristem's activity is