Vascular Bundle Arrangement in Dicot Stem

Steps:

• Recall that non-woody dicot stems have vascular bundles arranged in a ring within the cortex.
• Identify xylem as the inner component (towards pith) and phloem as the outer component (towards epidermis) in each bundle.
• Examine each photomicrograph for a ring of bundles with this xylem-phloem orientation.
• Select the image matching this eustele structure.

Why A is correct:

• Option A depicts vascular bundles in a ring with xylem inside and phloem outside, matching the dicot stem's collateral bundle definition.

Why the others are wrong:

• B shows scattered bundles, typical of monocot stems.
• C reverses xylem and phloem positions, incorrect for dicots.
• D lacks a ring arrangement, resembling root structure.

Final answer: A