What type of growth occurs primarily at the tips of roots and shoots?

Apical growth refers to the increase in length of a plant at the tips of its roots and shoots. This type of growth occurs in the apical meristems, which are regions of actively dividing cells located at the growing tips of these structures. Apical meristems are responsible for primary growth, allowing the plant to extend its height and depth, which is essential for reaching sunlight and accessing water and nutrients in the soil.

This growth is crucial for a plant's survival and adaptation as it influences how the plant will interact with its environment. In contrast to apical growth, lateral growth would typically involve the thickening of stems and roots, which is associated with secondary growth and usually occurs in woody plants. Main growth is not a standard term used in plant biology, and secondary growth refers specifically to increases in thickness and girth, rather than length. Thus, apical growth is identified distinctly as the process responsible for lengthening at the tips of roots and shoots.