Question

Lignified elongated dead cells are _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.
(a) Parenchyma
(b) Collenchyma
(c) Sclerenchyma
(d) None of these

Answer 1

Hint: These cells are a sort of protective tissue found in plants. These cells are specialized cells, consisting of dead cells at maturity. They provide the most structural support to a plant.

Complete answer:
Sclerenchyma is a sort of permanent tissue. These are elongated, dead cells with lignin deposits in their cell wall. The cell wall of sclerenchyma is thick and rigid. They need no intercellular gaps. Sclerenchyma is found within the covering of seeds and nuts, round the vascular tissues in stems, and the veins of leaves. Sclerenchyma provides strength to the plant. The cells are rigid and non stretchable and are basically present in the nongrowing area of plant bodies, like the bark or mature stems.
Sclerenchyma cells occur in many various shapes and sizes, but two main types occur: fibers and sclereids. Fibers are mainly elongated cells having long, tapering terminal interlock, and therefore giving maximum support to a plant. Sclereids are extremely different in shape and are found in several tissues of the plant, like the periderm, cortex, pith, xylem, and phloem.
Parenchyma cells are thin-walled, flexible, and loosely blood cells. They're living cells. Their shape changes as per function. Parenchymatous cells create ground tissue and pith.
These are stretched, living cells with minute intercellular gaps. Their cell walls are made from pectin and cellulose. Collenchyma is present within the marginal area of leaves and stems and provides flexibility with the structural framework and mechanical support to plants.

So, the correct answer is ‘Sclerenchyma’.

Note:
Sclerenchyma is seen throughout all plant tissues. These cells are found in mature parts of the plant like herbaceous perennials and woody plants. The cell wall is formed from waterproofing lignin. Sclerenchyma fibers have high economic importance, as they comprise the source material for several fabrics (such as flax, hemp, jute, and ramie).