Which tissue in plants can divide as needed?

The pericycle is the correct choice because it is a type of tissue in plants that is capable of division and plays a critical role in the growth and development of roots. It is located just inside the endodermis and is involved in the formation of lateral roots. This tissue can continuously divide throughout the life of the plant, enabling it to produce new roots as needed, which supports the plant's adaptability to its environment by enhancing its ability to absorb water and nutrients.

In contrast, xylem and phloem are primarily responsible for the transport of water, nutrients, and food. While they have some capacity for growth, they do not typically divide in the way that pericycle cells do. The cortex, which lies between the epidermis and the vascular tissue, serves mainly for storage and does not have the same regenerative capability. Therefore, the unique regenerative ability of the pericycle makes it the correct answer.