Question

Which of the following best describes collateral vascular bundles in dicot stems?

• A. Xylem and phloem arranged on alternate radii
• B. Xylem internal and phloem external with cambium in between
• C. Phloem completely surrounds xylem
• D. Xylem external and phloem internal

Answer 1

Answer:

B. Xylem internal and phloem external with cambium in between

In a collateral vascular bundle, the xylem and phloem are positioned on the same radius. In the specific case of dicot stems, these bundles are typically "open," meaning they possess a layer of meristematic tissue called cambium that allows for secondary growth (thickening of the stem). Phloem: Located toward the outside (periphery) of the stem. Xylem: Located toward the center (pith) of the stem. Cambium: A thin strip of cells sandwiched between the two, acting as a "growth engine."