Question

Arrange the layers of tissues from the centre to periphery as observed in a woody dicot stem. A. Vascular cambium B. Periderm C. Primary xylem D. Secondary phloem E. Secondary xylem. Choose the correct answer from the options given below:

• A. B, D, E, A, C
• B. C, A, E, D, B
• C. B, D, A, C, E
• D. C, A, B, D, E

Hint:

Centre to periphery: primary xylem, vascular cambium, secondary xylem, secondary phloem, periderm.

Answer 1

The Correct Option is B

Step 1: Understanding the Question:

• We must arrange the tissue layers of a woody (secondary) dicot stem from the centre outwards.

Step 2: Detailed Explanation:

• At the very centre lies the pith, followed by the primary xylem (C), which is the oldest xylem.

• The vascular cambium (A) lies between the xylem and the phloem; it cuts off secondary xylem (E) on its inner side and secondary phloem (D) on its outer side.

• The outermost protective layer, replacing the epidermis, is the periderm (B).

• Sequence from centre to periphery: Primary xylem (C) - Vascular cambium (A) - Secondary xylem (E) - Secondary phloem (D) - Periderm (B).

Step 3: Final Answer:
The correct option is (B) C, A, E, D, B.