Question

In conifers fibers are likely to be absent in
A) Secondary Phloem
B) Secondary Xylem
C) Primary Phloem
D) Leaves

Answer 1

Hint:Conifers are cone-bearing plants. Most of them are trees; others are shrubs. Formally, they are the Pinophyta or Coniferophyta Division.Conifers were the primary food of herbivorous dinosaurs, and their resins and poisons certainly offered some defence against herbivores.

Complete answer:
Stems light up the photosynthetic leaves and provide a nutrient pathway between the leaves and the roots. Most of the diameter of mature conifer stems consists of secondary xylem (wood) formed by the vascular cambium, a permanent cylinder of dividing cells lying just inside the bark.
The conifer wood is usually more uniform and simpler in structure than that of flowering plants. One type of cell, the tracheid, serves both to carry water and to support the trunk so that the conifers lack the more textured wood associated with the mixture of the elements of the vessel and the fibres of the hardwoods.
The vessel elements or part of a vessel is one of the types of cells found in xylem, the water that conducts the tissue of a plant. Vessel components are usually present in flowering plants (angiosperms) but are absent from most gymnosperms such as conifers. Vessel elements are the key attribute that separates the "hardwood" of angiosperms from the "softwood" of conifers.
In this case, the vascular stem cylinder is eustelic, consisting of joint, collateral, open and endarch vascular bundles. The ducts of resin are current. Secondary xylene is homogeneous (i.e. vessels are absent) and pycnoxylic.

Thus the correct answer is Option (B) Secondary xylem.

Note:Conifer species can be found in almost every part of the world and are often the most common plants in their habitats, as in the taiga. Conifers are of great economic importance, and their wood is primarily used in the manufacture of wood and paper. The conifer wood is known as softwood, while the yew wood is actually very rough. The Coniferae division includes about 700 living species.