- A Primary growth occurs mainly in roots; secondary growth occurs mainly in stems in the majority of cases studied
- B Primary = increase in length (apical meristems); secondary = increase in girth (lateral meristems)
- C Primary growth is seen mainly in angiosperms; secondary growth mainly in gymnosperms as widely reported
- D Primary growth is mostly vegetative; secondary growth is mostly reproductive in nature in standard practice
Correct answer: B. Primary = increase in length (apical meristems); secondary = increase in girth (lateral meristems)
Explanation: Primary growth occurs at apical meristems (shoot and root tips), causing elongation. Secondary growth occurs at lateral meristems (vascular cambium and cork cambium), causing increase in girth. Only dicots and gymnosperms show significant secondary growth.
Concept context
Internal tissue organisation: meristems, permanent tissues (xylem, phloem, parenchyma), and secondary growth. Frequently tested in NEET.