Question

Bast fibers are
(a)Sclerenchyma fibres
(b)Phloem fibres
(c)Libriform fibres
(d)Fibres tracheids

Answer 1

These cells contain cell walls with fine primary walls and normally stay alive after they get mature. They produce filler tissue in the weak areas of plants and commonly present in areas such as cortex, pericycle, pith, etc. They give structural support to the transporting cells.

Complete answer:
Bast fibers are phloem fibers. Sclerenchyma fibers are thin-lengthy, spindle fibers. The cells of sclerenchyma have tapering cell end walls.
Phloem fibers are basically sclerenchyma fibers that are found in the phloem, commonly known as bast fibers. They provide support to transport cells of the phloem and give structural strength to the stem of the several plants.

Additional Information: -Libriform fibers and fiber tracheids are the common xylem fibers which have thick walls and xylem fibers intermediate among tracheids.
-Sclerenchyma cells that contain strong secondary walls and mostly die when they get mature. The major mechanical support to the plant is given by Sclerenchyma.
- Herbs such as flax, hemp, ramie, etc. and trees like lime, linden, wisteria are plant species that produce high bast fibres.
So, the correct answer is Phloem fibres.

Note: The extracted bast fibers are rich in cellulose and lignin, due to which they are often used in the papermaking industry, where the bast fibers undergo pulping and bleaching to form papers.
-Hemp is an industrially important herb, which is a member of the Cannabis species that is cultivated for the specific industry and for the accessory secondary products.
-Due to the increasing plastic pollution, biodegradable products are highlights of this decade, where this fastest-growing herb finds its industrial significance.