Question

Fiber tracheids have
a. Simple pits
b. Thick walls
c. Bordered pits
d. Pits with small borders

Answer 1

Hint: Fiber is a natural substance and it is a biological compound which is long in size and its wideness and they are found in plants, and animals in various forms and they have many uses and they also produce synthetically for commercial purposes.

Complete answer:
Plants consist of various components such as roots, stems, leaves which have different functions and the vascular bundles which are made for transport of water and minerals and food to different parts of the plants, and this Vascular bundles are Xylem and Phloem, where they contain various components such as vessels, parenchyma cells and fibers.
Xylem fibers are generally of two types, they are fiber tracheids and libriform fibers, and this division is mainly based on the arrangement of pits and thickness of the walls.

> Fiber tracheid:
- These are longer and they have thicker cell walls and they have simple pits unlike tracheid which have bordered pits, and in fiber tracheids they are shorter in length and have thinner cell walls so they are called simple pits.
- In these plants the border of the pits are much reduced when compared to tracheids.
- Because of this pit chamber becomes smaller than tracheids and the inner aperture appears as a slit due to thickening and it is usually formed at right angle to outer aperture.

> Libriform fiber:
- These are longer and they also have thicker cell walls and they also have simple pits compared to that of tracheids.
- In this type, the canal of the pit is longer and the inner aperture of the pit pair appears slit like due to wall thickening and it is usually formed right angled to the outer aperture.

Hence, the correct answer is option (A).

Note: Fibers are generally used in the field of textile industry as a filling, and they are also used in the preparation of ropes and brushes, Brooms and fibers which are commercially used are of 2 types, one having thin lignin on cell wall and other having thick lignin which are harder in nature.