Secondary Medullary Rays

Q. Secondary medullary rays are formed by the activity of

1. Cork cambium
2. Vascular cambium
3. Secondary cortex
4. Secondary phloem

Q. Which of the following is responsible for the formation of secondary medullary rays?

1. Growth of secondary xylem
2. Growth of Cambium through secondary xylem and seoondary phloem
3. Growth of secondary phloem into secondary xylem
4. None of the above

Q. Choose the correct statement with respect to medullary rays.

1. Medullary rays may be parenchymatous or collenchymatous in nature
2. Primary medullary rays are present inside primary vascular bundles
3. Secondary medullary rays are formed by the cork cambium
4. They help in radial conduction of food and water