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(b) xylotomy

(b) Hevea brasiliensis

(b) Acacia Senegal

In plants with long fusiform initials, they strongly overlap at the ends, and this type of cambium is called non – storied (non – startified) cambium.

If the fusiform initials are arranged in horizontal tiers, with the end of the cells of one tier appearing at approximately the same level, as seen in Tangential Longitudinal Section (TLS), it is called storied (stratified) cambium.

(b) (i) is not correct but (ii) and (iii) are correct

(a) In temperate regions, the cambium is very active in winter season.

(d) treachery elements, fibers and wood parenchyma

Apical meristems produce the primary plant body. In some plants, the lateral meristem increase the girth of a plant. This type of growth is secondary because the lateral meristem are not directly produced by apical meristems. 

Woody plants have two types of lateral meristems: a vascular cambium that produces xylem, phloem tissues and cork cambium that produces the bark of a tree.

The secondary growth in dicots and gymnosperms is brought about by two lateral meristems.

1. Vascular Cambium and 

2. Cork Cambium

1. Primary growth: The plant organs originating from the apical meristems pass through a period of expansion in length and width. The roots and stems grow in length with the help of apical meristems. This is tailed primary growth or longitudinal growth.

2. Secondary growth: The gymnosperms and most angiosperms, including some monocots, show an increase in thickness of stems and roots by means of secondary growth or latitudinal growth.

Whenever stems and roots increase in thickness by secondary growth, the periderm, a protective tissue of secondary origin replaces the epidermis and Often primary cortex. The periderm consists of phellem, phellogen, and phelloderm.

Secondary phloem is a living tissue that transports soluble organic compounds made during photosynthesis to various parts of plant.

(b) more durable and more resistant to the attack of micro organism and insects

It is a branch of dendrochronology concerned with constructing records of past climates and climatic events by analysis of tree growth characteristics, especially growth rings

(d) The sap wood conducts minerals, while the heart wood conduct water

The secondary xylem, also called wood, is formed by a relatively complex meristem, the vascular cambium, consisting of vertically (axial) elongated fusiform initials and horizontally (radially) elongated ray initials.

(c) apical meristem

The pores of the early wood are distinctly larger than those of the late wood. Thus rings of wide and narrow vessels occur.

(a) secondary xylem and secondary phloem

(c) Abies balsamea

(d) secondary growth

In many dicot plants, the lumen of the xylem vessels is blocked by many balloon like ingrowths from the neighbouring parenchymatous cells. These balloons like structure are called tyloses.

(d) starchy crystals, resins, gums, oils, tannins or colored substances are present

Diffuse porous woods are woods in which the vessels or pores are rather uniform in size and distribution throughout an annual ring. eg: Ace

When the bark is damaged, the phellogem forms a complete cylinder around the stem and it gives rise to ring barks.

(b) diffuse porous

(d) 3500 years

The annual ring denotes the combination of early wood and late wood and the ring becomes evident to our eye due to the high density of late wood. Sometimes annual rings are called growth rings.

(b) adverse natural calamities

(c) palaeology

(c) secondary cortex

(b) Phellogen