Solution:Sclerenchyma is a dead permanent tissue. Its cells These have heavily thickened secondary walls containing lignin. The cells are rigid, non-stretchable and lack protoplasma.
They provide protection and mechanical support to plant. They are usually found in non-growing regions of plant bodies such as the bark protective layering of seeds and fruits or mature stems.
Rest epithelium, paranchyma and collenchyma have living tissues.