Which of the following permanent tissue shows characteristic thickening on the primary cell wall?
Angular collenchyma
Lamellar collenchyma
Lacunar collenchyma
All of these
The cell walls of collenchyma are their distinctive features that show uneven thickenings. Angular collenchyma, Lamellar collenchyma and Lacunar collenchyma are the types of collenchyma based on the thickening pattern.