Question

In trees, the growth rings represent

• A. Primary xylem
• B. Secondary xylem
• C. Secondary phloem
• D. Cambrium

Answer 1

The correct option is B Secondary xylem

A growth layer in secondary xylem seen in a cross section of a woody stem or branch. A layer of wood formed in a plant during a single period of growth. Growth rings are visible as concentric circles of varying width when a tree is cut crosswise. They represent layers of cells produced by the tissue known as vascular cambium. Most growth rings reflect a full year's growth and are called as annual rings. But abrupt changes in the environment, especially in the availability of water, can cause a plant to produce more than one growth ring in a year. So, in trees the growth rings represents secondary xylem and not primary xylem, secondary phloem and cambrium.
Therefore, the correct answer is option B.