It is a true statement.
The plan cell wall is composed of 3 layers or 3 types of walls:Primary cell wall.Secondary cell wall.Middle lamella.
Between primary and secondary there is middle lamella.
These layer make it a laminated two layer structure.
small, big, or no change could occur in the phenotype. it could cause something as simple as a cats ears to curl backwards or something as frighting as death. it could also occur in the protien-coding area and have an effect on that but no effect on the amino acids. what has to occur is a changing in the hox gene or the control gene.