The correct option is Shoot and root apical meristems.
Explanation
Plant growth is generally classified into two types: primary growth and secondary growth. Primary growth refers to the increase in the length of the plant body, occurring at the tips of roots and shoots. Secondary growth refers to the increase in the girth or thickness of the plant.
Detailed Analysis
- Apical Meristems (Correct): These are located at the tips of roots and shoots. They are responsible for the production of new cells that elongate the plant axis. This process constitutes primary growth.
- Lateral Meristems (Incorrect): These include the vascular cambium and cork cambium. They appear later in the life of a plant (in gymnosperms and dicots) and are responsible for increasing the diameter or girth of the axis. This process is known as secondary growth.
- Cork Cambium (Incorrect): Also known as phellogen, this is a type of lateral meristem responsible for producing the protective outer bark (periderm) during secondary growth.
- Interfascicular Cambium (Incorrect): This is a meristematic tissue that develops between vascular bundles. It joins with the intrafascicular cambium to form a complete ring of vascular cambium, which drives secondary growth.
Key Takeaway
Primary growth is driven by apical meristems and results in an increase in length. Secondary growth is driven by lateral meristems (vascular and cork cambium) and results in an increase in girth.