Unit 4 · Plant Form and Function
How the vascular cambium and cork cambium thicken woody dicot stems and roots: secondary xylem (wood) and phloem, annual rings, heartwood and sapwood, bark, lenticels and why monocots lack secondary growth.
Deshapriya Senevirathne. B.Sc. (Hons) Biology Special, University of Peradeniya — graduated with a class pass. All the content and lessons in A/L Biology on Paadama are reviewed by Deshapriya Senevirathne, and the lessons are taught by him.