Question

Tracheary elements of protoxylem are

• A. Larger and broader
• B. Formed towards the end
• C. With advanced type of thickenings
• D. Short narrow with primitive type of thickenings

Answer 1

The correct option is D Short narrow with primitive type of thickenings

Protoxylem tracheary elements form during primary plant growth and deposit localized annular or helical secondary cell wall thickenings (primitive type), reinforcement patterns that allow these cells to continue to elongate within actively growing areas of the plant.

So, the correct answer is 'Short narrow with primitive type of thickenings.'