What is the growing layer of a plant known as?

The growing layer of a plant is known as cambium, which plays a crucial role in the growth of the plant's stems and roots. Cambium is a type of lateral meristem, responsible for secondary growth, which allows the plant to increase in thickness. This layer produce new phloem cells on the outside and new xylem cells on the inside, contributing to the plant's overall growth and ability to transport nutrients and water.

Understanding cambium's function is essential in plant biology, as it underlines the process of how plants can sustain their growth over time, adapting to their environment and increasing their structural integrity. Some other terms listed, like phloem and xylem, refer to specific types of tissues that carry nutrients and water, respectively, but they do not refer to the active growing layer itself. The meristem is related as it encompasses all types of growth tissue, including cambium, but the specific function of producing new growth layers is attributed to cambium in established plants.