Question 1: Palette 1/89

NEET 2026 MCQ

The main function of bulliform cells in grasses is :

A

to make the leaf impermeable to fungal spores.

B

to transport water.

C

to perform photosynthesis.

D

to minimize water loss during water stress.

Question 2: Palette 2/89

NEET 2026 MCQ

$ \text { Match List-I with List-II : } $

List-I (Phase of cell cycle)		List-II (Activity)
A.	Conjunctive tissue	I.	Specialised cells in the vicinity of guard cells
B.	Casparian strips	II.	Endodermal cells rich in starch
C.	Subsidiary cells	III.	Tissue between xylem and phloem
D.	Starch sheath	IV.	Endodermal cells with suberin deposition

Choose the correct answer from the options given below :

A

A-IV, B-III, C-I, D-II

B

A-III, B-IV, C-II, D-I

C

A-III, B-IV, C-I, D-II

D

A-IV, B-III, C-II, D-I

Question 3: Palette 3/89

NEET 2025 MCQ

In the seeds of cereals, the outer covering of endosperm separates the embryo by a protein-rich layer called:

A

Integument

B

Aleurone layer

C

Coleoptile

D

Coleorhiza

Question 4: Palette 4/89

NEET 2025 MCQ

Find the statement that is NOT correct with regard to the structure of monocot stem.

A

Vascular bundles are conjoint and closed.

B

Phloem parenchyma is absent.

C

Hypodermis is parenchymatous.

D

Vascular bundles are scattered.

Question 5: Palette 5/89

NEET 2024 MCQ

Which of the following simple tissues are commonly found in the fruit walls of nuts and pulp of pear?

A

Sclereids

B

Fibres

C

Parenchyma

D

Collenchyma

Question 6: Palette 6/89

NEET 2024 MCQ

Given below are two statements:

Statement I: In a dicotyledonous leaf, the adaxial epidermis generally bears more stomata than the abaxial epidermis.

Statement II: In a dicotyledonous leaf, the adaxially placed palisade parenchyma is made up of elongated cells, which are arranged vertically and parallel to each other.

In the light of the above statements, choose the correct answer from the options given below:

A

Statement I is true but Statement II is false

B

Statement I is false but Statement II is true

C

Both Statement I and Statement II are true

D

Both Statement I and Statement II are false

Question 7: Palette 7/89

NEET 2024 MCQ

In the given figure, which component has thin outer walls and highly thickened inner walls?

A

C

B

D

C

A

D

B

Question 8: Palette 8/89

NEET 2024 MCQ

Given below are two statements:

Statement I : Parenchyma is living but collenchyma is dead tissue.

Statement II : Gymnosperms lack xylem vessels but presence of xylem vessels is the characteristic of angiosperms.

In the light of the above statements, choose the correct answer from the options given below:

A

Both Statement I and Statement II are true

B

Both Statement I and Statement II are false

C

Statement I is true but Statement II is false

D

Statement I is false but Statement II is true

Question 9: Palette 9/89

NEET 2024 MCQ

Which of the following helps in maintenance of the pressure gradient in sieve tubes?

A

Albuminous cells

B

Sieve cells

C

Phloem parenchyma

D

Companion cells

Question 10: Palette 10/89

NEET 2023 MCQ

The transverse section of a plant part showed polyarch, radial and exarch xylem, with endodermis and pericycle. The plant part is identified as :

A

Monocot root

B

Dicot root

C

Dicot stem

D

Monocot stem

Question 11: Palette 11/89

NEET 2023 MCQ

Consider the following tissues in the stelar region of a stem showing secondary growth.

(A) Primary xylem

(B) Secondary xylem

(C) Primary phloem

(D) Secondary phloem

Arrange these in the correct sequence of their position from pith towards corts.

A

(A), (B), (D), (C)

B

(B), (A), (C), (D)

C

(A), (B), (C), (D)

D

(B), (A), (D), (C)

Question 12: Palette 12/89

NEET 2023 MCQ

Consider the following plant tissues :

(A) Axillary buds

(B) Fascicular vascular cambium

(C) Interfascicular cambium

(D) Cork cambium

(E) Intercalary meristem

Identify the lateral meristems among the above.

A

(A), (C) and (D) only

B

(B), (C) and (D) only

C

(A), (B), (C) and (E) only

D

(A), (B), (D) and (E) only

Question 13: Palette 13/89

NEET 2023 MCQ

Given below are two statements : One is labelled as Assertion A and the other is labelled as Reason R :

Assertion A : Late wood has fewer xylary elements with narrow vessels.

Reason R : Cambium is less active in winters.

In the light of the above statements, choose the correct answer from the options given below :

A

Both A and R are true but R is NOT the correct explanation of A

B

A is true but R is false

C

A is false but R is true

D

Both A and R are true and R is the correct explanation of A

Question 14: Palette 14/89

NEET 2023 MCQ

Given below are two statements :

Statement I : Endarch and exarch are the terms often used for describing the position of secondary xylem in the plant body.

Statement II : Exarch condition is the most common feature of the root system.

In the light of the above statements, choose the correct answer from the options given below:

A

Both Statement I and Statement II are false

B

Statement I is correct but Statement II is false

C

Statement I is incorrect but Statement II is true

D

Both Statement I and Statement II are true

Question 15: Palette 15/89

NEET 2022 MCQ

Interfascicular cambium is present between

A

Secondary xylem and secondary phloem

B

Primary xylem and primary phloem

C

Pericycle and endodermis

D

Two vascular bundles

Question 16: Palette 16/89

NEET 2022 MCQ

Initiation of lateral roots and vascular cambium during secondary growth takes place in cells of

A

Pericycle

B

Epiblema

C

Cortex

D

Endodermis

Question 17: Palette 17/89

NEET 2022 MCQ

"Girdling Experiment" was performed by Plant Physiologists to identify the plant tissue through which:

A

water is transported

B

food is transported

C

for both water and food transportation

D

osmosis is observed

Question 18: Palette 18/89

NEET 2022 MCQ

Read the following statements about the vascular bundles:

(a) In roots, xylem and phloem in a vascular bundle are arranged in an alternate manner along the different radii.

(b) Conjoint closed vascular bundles do not possess cambium

(c) In open vascular bundles, cambium is present in between xylem and phloem

(d) The vascular bundles of dicotyledonous stem possess endarch protoxylem

(e) In monocotyledonous root, usually there are more than six xylem bundles present

Choose the correct answer from the options given below :

A

(a), (b) and (d) only

B

(a), (b), (c), (d) and (e) only

C

(a), (b), (c) and (d) only

D

(a), (c), (d) and (e) only

Question 19: Palette 19/89

NEET 2022 MCQ

In old trees the greater part of secondary xylem is dark brown and resistant to insect attack due to :

(a) secretion of secondary metabolities and their deposition in the lumen of vessels.

(b) deposition of organic compounds like tannins and resins in the central layers of stem.

(c) deposition of suberin and aromatic substances in the outer layer of stem.

(d) deposition of tannins, gum, resin and aromatic substances in the peripheral layers of stem.

(e) presence of parenchyma cells, functionally active xylem elements and essential oils.

Choose the correct answer from the options given below :

A

(a) and (b) only

B

(c) and (d) only

C

(d) and (e) only

D

(b) and (d) only

Question 20: Palette 20/89

NEET 2022 MCQ

what is the role of large bundle sheath cells found around the vascular bundles in C₄ plants?

A

To provide the site for photorespiratory pathway

B

To increase the number of chloroplast for the operation of Calvin cycle

C

To enable the plant to tolerate high temperature

D

To protect the vascular tissue from high light intensity

Question 21: Palette 21/89

NEET 2022 MCQ

The anatomy of springwood shows some peculiar features. Identify the correct set of statements about springwood.

(a) It is also called as the earlywood

(b) In spring season cambium produces xylem elements with narrow vessels

(c) It is lighter in colour

(d) The springwood along with autumn wood shows alternate concentric rings forming annual rings

(e) It has lower density

Choose the correct answer from the options given below:

A

(a), (b), (d) and (e) only

B

(a), (c), (d) and (e) only

C

(a), (b) and (d) only

D

(c), (d) and (e) only

Question 22: Palette 22/89

NEET 2021 MCQ

Match List-I with List-II.

	List-I		List-II
(a)	Lenticels	(i)	Phellogen
(b)	Cork cambium	(ii)	Suberin deposition
(c)	Secondary cortex	(iii)	Exchange of gases
(d)	Cork	(iv)	Phelloderm

Choose the correct answer from the options given below.

A

(a)	(b)	(c)	(d)
(iv)	(ii)	(i)	(iii)

B

(a)	(b)	(c)	(d)
(iv)	(i)	(iii)	(ii)

C

(a)	(b)	(c)	(d)
(iii)	(i)	(iv)	(ii)

D

(a)	(b)	(c)	(d)
(ii)	(iii)	(iv)	(i)

Question 23: Palette 23/89

NEET 2021 MCQ

Match List-I with List-II.

	List-I		List-II
(a)	Cells with active cell division capacity	(i)	Vascular tissues
(b)	Tissue having all cells similar in structure and function	(ii)	Meristematic tissue
(c)	Tissue having different types of cells	(iii)	Sclereids
(d)	Dead cells with highly thickened walls and narrow lumen	(iv)	Simple tissue

Select the correct answer from the options given below.

A

(a)	(b)	(c)	(d)
(iii)	(ii)	(iv)	(i)

B

(a)	(b)	(c)	(d)
(ii)	(iv)	(i)	(iii)

C

(a)	(b)	(c)	(d)
(iv)	(iii)	(ii)	(i)

D

(a)	(b)	(c)	(d)
(i)	(ii)	(iii)	(iv)

Question 24: Palette 24/89

NEET 2021 MCQ

Select the correct pair.

A

Loose parenchyma cells rupturing the epidermis and forming a lens shaped opening in bark - Spongy parenchyma

B

Large colorless empty cells in the epidermis of grass leaves - Subsidiary cells

C

In dicot leaves, vascular bundles are surrounded by large thick-walled cells - Conjunctive tissue

D

Cells of medullary rays that form part of cambial ring - Interfascicular cambium

Question 25: Palette 25/89

NEET 2020 MCQ

Identify the incorrect statement.

A

Sapwood is involved in conduction of water and minerals from root to leaf

B

Sapwood is the innermost secondary xylem and is lighter in colour

C

Due to deposition of tannins, resins, oils etc., heart wood is dark in colour

D

Heart wood does not conduct water but gives mechanical support

Question 26: Palette 26/89

NEET 2020 MCQ

The roots that originate from the base of the stem are

A

Primary roots

B

Prop roots

C

Lateral roots

D

Fibrous roots

Question 27: Palette 27/89

NEET 2020 MCQ

The transverse section of a plant shows following anatomical features :

(i) Large number of scattered vascular bundles surrounded by bundle sheath
(ii) Large conspicuous parenchymatous ground tissue
(iii) Vascular bundles conjoint and closed
(iv) Phloem parenchyma absent

Identify the category of plant and its part:

A

Monocotyledonous root

B

Dicotyledonous stem

C

Dicotyledonous root

D

Monocotyledonous stem

Question 28: Palette 28/89

NEET 2019 MCQ

Phloem in gymnosperms lacks :

A

Companion cells only

B

Both sieve tubes and companion cells

C

Albuminous cells and sieve cells

D

Sieve tubes only

Question 29: Palette 29/89

NEET 2019 MCQ

What is the direction of movement of sugars in phloem?

A

Downward

B

Bi-directional

C

Non-multidirectional

D

Upward

Question 30: Palette 30/89

NEET 2019 MCQ

Which of the statements given below is not true about formation of Annual Rings in trees?

A

Activity of cambium depends upon variation in climate.

B

Annula ring are not prominent in trees of temperate region.

C

Annula ring is a combination of spring wood and autumn wood produced in a year.

D

Differential activity of cambium causes light and dark bands of tissue-early and late wood respectively

Question 31: Palette 31/89

NEET 2018 MCQ

Stomata in grass leaf are

A

kidney-shaped

B

barrel-shaped

C

dumb-bell shaped

D

rectangular

Question 32: Palette 32/89

NEET 2018 MCQ

Secondary xylem and phloem in dicot stem are produced by

A

vascular cambium

B

axillary meristems

C

apical meristems

D

phellogen

Question 33: Palette 33/89

NEET 2018 MCQ

Casparian strips occur in

A

pericycle

B

epidermis

C

endodermis.

D

cortex

Question 34: Palette 34/89

NEET 2018 MCQ

Plants having little or no secondary growth are

A

deciduous angiosperms

B

grasses

C

cycads

D

conifers

Question 35: Palette 35/89

NEET 2017 MCQ

Identify the wrong statement in context of heartwood :

A

It is highly durable.

B

It comprises dead elements with highly lignified walls

C

It conducts water and minerals efficiently

D

Organic compounds are deposited in it

Question 36: Palette 36/89

NEET 2017 MCQ

The vascular cambium normally gives rise to :

A

Primary phloem

B

Secondary xylem

C

Periderm

D

Phelloderm

Question 37: Palette 37/89

NEET 2017 MCQ

Root hairs develop from the region of :

A

Meristematic activity

B

Root cap

C

Maturation

D

Elongation

Question 38: Palette 38/89

NEET 2017 MCQ

Which of the following is made up of dead cells ?

A

Collenchyma

B

Xylem parenchyma

C

Phellem

D

Phloem

Question 39: Palette 39/89

NEET 2016 MCQ

Cortex is the region found between -

A

endodermis and pith

B

endodermis and vascular bundle

C

epidermis and stele

D

pericycle and endodermis

Question 40: Palette 40/89

NEET 2016 MCQ

The balloon-shaped structures called tyloses

A

are extensions of xylem parenchyma cells into vessels

B

originate in the lumen of vessels

C

are linked to the ascent of sap through xylem vessels

D

characterize the sapwood

Question 41: Palette 41/89

NEET 2016 MCQ

Specialised epidermal cells surrounding the guard cells are called -

A

Lenticels

B

Complementary cells

C

Bulliform cells

D

Subsidiary cells

Question 42: Palette 42/89

NEET 2015 MCQ

Read the different components from (1) to (4) in the list given below and tell the correct order of the components with reference to their arrangement from outer side to inner side in a woody dicot stem :
(1) Secondary cortex
(2) Wood
(3) Secondary phoem
(4) Phellem
The correct order is :

A

(3), (4), (2), (1)

B

(4), (1), (3), (2)

C

(4), (3), (1), (2)

D

(1), (2), (4), (3)

Question 43: Palette 43/89

NEET 2015 MCQ

Vascular bundles in monocotyledons are considered closed because

A

There are no vessels with perforations

B

Xylem is surrounded all around by phloem

C

A bundle sheath surrounds each bundle

D

Cambium is absent

Question 44: Palette 44/89

NEET 2015 MCQ

A major characteristic of the monocot root is the presence of :

A

Vasculature without cambium

B

Cambium sandwiched between phloem and xylem along the radius

C

Open vascular bundles

D

Scattered vascular bundles

Question 45: Palette 45/89

NEET 2014 MCQ

You are given a fairly old piece of dicot stem and a dicot root. Which of the following anatomical structures will you use to distinguish between the two?

A

Secondary xylem

B

Protoxylem

C

Secondary phloem

D

Cortical cells

Question 46: Palette 46/89

NEET 2014 MCQ

Tracheids differ from other tracheary elements in :

A

being imperforate

B

having casparian strips

C

lacking nucleus

D

being lignified

Question 47: Palette 47/89

NEET 2013 MCQ

Meristematic tissue responsible for increase in girth of tree trunk is :

A

Phellogen

B

Intercalary meristem

C

Apical meristem

D

Lateral meristem

Question 48: Palette 48/89

NEET 2013 MCQ

Which of the following statements is not true for stomatal apparatus ?

A

Stomata are involved in gaseous exchange

B

Inner walls of guard cells are thick

C

Guard cells invariably posses chloroplasts and mitochondria

D

Guard cells are always surrounded by subsidiary cells

Question 49: Palette 49/89

NEET 2013 MCQ

Bundle sheath cells :

A

lack both RuBisCo and PEP carboxylase

B

are rich in PEP carboxylase

C

are rich in RuBisCo

D

lack RuBisCo

Question 50: Palette 50/89

NEET 2013 MCQ

Interfascicular cambium develops from the cells of :

A

Endodermis

B

Pericycle

C

Medullary rays

D

Xylem parenchyma

Question 51: Palette 51/89

NEET 2013 MCQ

Lenticels are involved in

A

Food transport

B

Photosynthesis

C

Transpiration

D

Gaseous exchange

Question 52: Palette 52/89

NEET 2013 MCQ

Age of a tree can be estimated by :

A

Diameter of its heartwood

B

Number of annual rings

C

Its height and girth

D

Biomass

Question 53: Palette 53/89

NEET 2012 MCQ

As compared to a dicot root, a monocot root has

A

More abundant secondary xylem

B

Relatively thicker periderm

C

Many xylem bundles

D

Inconspicuous annual rings

Question 54: Palette 54/89

NEET 2012 MCQ

Closed vascular bundles lack

A

Ground tissue

B

Conjunctive tissue

C

Cambium

D

Pith

Question 55: Palette 55/89

NEET 2012 MCQ

Gymnosperms are also called soft wood spermatophytes because they lack

A

Cambium

B

Thick - walled tracheids

C

Phloem fibres

D

Xylem fibres

Question 56: Palette 56/89

NEET 2012 MCQ

Companion cells are closely associated with

A

Sieve elements

B

Trichomes

C

Vessel elements

D

Guard cells

Question 57: Palette 57/89

NEET 2012 MCQ

Water containing cavities in vascular bundles are found in

A

Maize

B

Cycas

C

Sunflower

D

Pinus

Question 58: Palette 58/89

NEET 2012 MCQ

The common bottle cork is a product of

A

Phellogen

B

Xylem

C

Vascular Cambium

D

Dermatogen

Question 59: Palette 59/89

NEET 2011 MCQ

Some vascular bundles are described as open because these :

A

are capable of producing secondary xylem and phloem

B

are not surrounded by pericycle

C

possess conjunctive tissue between xylem and phloem

D

are surrounded by pericycle but no endodermis

Question 60: Palette 60/89

NEET 2011 MCQ

Function of companion cells is :

A

Providing water to phloem

B

Loading of sucrose into sieve elements

C

Loading of sucrose into sieve elements by passive transport

D

Providing energy to sieve elements for active transport

Question 61: Palette 61/89

NEET 2011 MCQ

Ground tissue includes :

A

All tissues external to endodermis

B

Epidermis and cortex

C

All tissues internal to endodermis

D

All tissues except epidermis and vascular bundles

Question 62: Palette 62/89

NEET 2011 MCQ

The cork cambium, cork and secondary cortex are collectively called :

A

Periderm

B

Phellem

C

Phellogen

D

Phelloderm

Question 63: Palette 63/89

NEET 2010 MCQ

Transport of food material in higher plants takes place through -

A

Sieve elements

B

Transfusion tissue

C

Companion cells

D

Tracheids

Question 64: Palette 64/89

NEET 2010 MCQ

Heartwood differs from sapwood in –

A

Having dead and non-conducting elements

B

Being susceptible to pests and pathogens

C

Presence of rays and fibres

D

Abscence of vessels and parenchyma

Question 65: Palette 65/89

NEET 2010 MCQ

Which one of the folliwng is not a lateral meristem ?

A

Interfascicular cambium

B

Intercalary meristem

C

Intrafascicular cambium

D

Phellogen

Question 66: Palette 66/89

NEET 2010 MCQ

The chief water conducting elements of xylem in gymnosperms are :

A

Fibres

B

Transfusion tissue

C

Vessels

D

Tracheids

Question 67: Palette 67/89

NEET 2009 MCQ

In barley stem vascular bundles are -

A

Closed and scattered

B

Closed and radial

C

Open and in a ring

D

Open and scattered

Question 68: Palette 68/89

NEET 2009 MCQ

Palisade parenchyma is absent in leaves of -

A

Mustard

B

Sorghum

C

Soybean

D

Gram

Question 69: Palette 69/89

NEET 2009 MCQ

The annular and spirally thickened conducting elements generally develop in the protoxylem when the root or stem is -

A

Maturing

B

Widening

C

Elongating

D

Differentiating

Question 70: Palette 70/89

NEET 2009 MCQ

Anatomically fairly old dicotyledonous root is distinguished from the dicotyledonous stem by :

A

Absence of secondary phloem

B

Presence of cortex

C

Position of protoxylem

D

Absence of secondary xylem

Question 71: Palette 71/89

NEET 2008 MCQ

Vascular tissues in flowering plants develop from:

A

plerome

B

periblem

C

phellogen

D

dermatogen

Question 72: Palette 72/89

NEET 2008 MCQ

The length of different internodes in a culm of sugarcane is variable because of:

A

shoot apical meristem

B

position of axillary buds

C

size of leaf lamina at the node below each internode

D

intercalary meristem

Question 73: Palette 73/89

NEET 2007 MCQ

Passage cells are thin-walled cells found in:-

A

Endodermis of roots facilitating rapid transport of water from cortex to pericycle

B

Testa of seeds to enable emergence of growing embryonic axis during seed germination.

C

Phloem elements that serve as entry points for substances for transport to other plant parts

D

Central region of style through which the pollen tube grows towards the ovary.

Question 74: Palette 74/89

NEET 2007 MCQ

For a critical study of secondary growth in plants, which one of the following pairs is suitable ?

A

Deodar and fern

B

Wheat and maiden hair fern

C

Sugarcane and sunflower

D

Teak and pine

Question 75: Palette 75/89

NEET 2006 MCQ

A common structural feature of vessel elements and sieve tube elements is-

A

Enucleate condition

B

Presence of p-protein

C

Thick secondary walls

D

Pores on lateral wall

Question 76: Palette 76/89

NEET 2005 MCQ

In a woody dicotyledonous tree, which of the following parts will mainly consist of primary tissues ?

A

Shoot tips and root tips

B

Flowers, fruit and leaves

C

Stem and root

D

All parts

Question 77: Palette 77/89

NEET 2004 MCQ

In a longitudinal section of a root, starting from the tip upward, the four zones occur in the following order :-

A

Cell division, cell enlargement, cell maturation, root cap

B

Root cap, cell division, cell enlargement, cell maturation

C

Root cap, cell division, cell maturation, cell enlargement

D

Celldivision,cell maturation, cell enlargement, root cap

Question 78: Palette 78/89

NEET 2003 MCQ

The apical meristem of the root is present

A

In all the roots

B

Only in tap roots

C

Only in adventitious roots

D

Only in radicals

Question 79: Palette 79/89

NEET 2003 MCQ

Diffuse porous wood is characteristics of those plants which are growing in : -

A

Tropics

B

Temperate climate

C

Alpine region

D

Cold winter regions

Question 80: Palette 80/89

NEET 2003 MCQ

The cells of the quiescent centre are characterised by : -

A

Having light cytoplasm and small nuclei

B

Dividing regularly to add to tunica

C

Having dense cytoplasm and prominent nuclei

D

Dividing regularly to add to the corpus

Question 81: Palette 81/89

NEET 2003 MCQ

Chlorenchyma is known to develop in the : -

A

Mycelium of a green mould such as Aspergillus

B

Pollen tube of Pinus

C

Cytoplasm of Chlorella

D

Spore capsule of a moss

Question 82: Palette 82/89

NEET 2003 MCQ

In which one of the following nitrogen is not a constituent ?

A

Pepsin

B

Invertase

C

Idioblast

D

Bacteriochlorophyll

Question 83: Palette 83/89

NEET 2003 MCQ

The aleurone layer in maize grain is specially rich in :-

A

Lipids

B

Proteins

C

Auxins

D

Starch

Question 84: Palette 84/89

NEET 2002 MCQ

Vessels are found in : -

A

Most of the angiosperm and few gymnosperms

B

All angiosperms and some gymnosperm

C

All pteridophyta

D

All angiosperms, all gymnosperms and some pteridophyta

Question 85: Palette 85/89

NEET 2002 MCQ

Four radial vascular bundle are found in : -

A

Monocot stem

B

Dicot stem

C

Dicot root

D

Monocot root

Question 86: Palette 86/89

NEET 2002 MCQ

Axillary bud and terminal bud derived from the activity of : -

A

Apical meristem

B

Parenchyma

C

Lateral meristem

D

Intercalary meristem

Question 87: Palette 87/89

NEET 2002 MCQ

Which of the following statement is true ?

A

Tracheids are unicellular and with wide lumen

B

Tracheids are multicellular and with narrow lumen

C

Vessels are multicellular and with wide lumen

D

Vessels are unicellular and with narrow lumen

Question 88: Palette 88/89

NEET 2001 MCQ

In plants inulin and pectin are

A

Excretory material

B

Reserved material

C

Insect attracting material

D

Wastes

Question 89: Palette 89/89

NEET 2000 MCQ

What happens in plants during vascularisation ?

A

Formation of procambium, primary phloem and xylem simultaneousl

B

Differentiation of procambium followed by the formation of secondary xylem

C

Differentiation of procambium, formation of primary phloem followed by formation of primary xylem

D

Differentiation of procambium followed by the formation of primary phloem and xylem simultaneously