The constantly dividing cells found at the apex of roots and stem during growth is

The question describes cells that are constantly dividing and are found at the apex (tip) of roots and stems. These are meristematic cells, which form the meristematic tissue (meristem).

Meristematic cells are undifferentiated cells that retain the ability to divide continuously by mitosis. They are responsible for primary growth in plants, adding length to roots and shoots. The key characteristic that defines meristematic tissue is its capacity for active and continuous cell division, which is exactly what the question describes.

The other options describe types or locations of meristems rather than the fundamental nature of the cells:

• Apical refers to the location of the meristem (at the apex/tip), not the type of cells themselves. Apical meristem is made up of meristematic cells, but "apical" describes where the meristem is, not what the constantly dividing cells are called.
• Intercalary meristems are found at the base of internodes (e.g., in grasses), not at the apex of roots and stems.
• Lateral meristems (such as the cambium) are responsible for secondary growth (increase in girth), not primary growth at the tips.

The question asks what type of cells these are. The answer is meristematic, because the defining property of these cells is their ability to divide indefinitely.