Secondary Growth — NEET Biology MCQs with Solutions
Free NEET Biology Secondary Growth MCQs with step-by-step solutions (34 questions). Part of Anatomy of Flowering Plants. Practise online on Prepizo — no login needed.
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Questions with solutions
Q1 — Secondary Growth · medium · theory
Which of the following statements about cork cambium is incorrect?
A. It is responsible for the formation of lenticels
B. It is a couple of layers thick
C. It forms a part of periderm
D. It forms secondary cortex on its outerside ✓ Correct
Solution: Cork cambium (phellogen) forms cork (phellem) on its outer side and secondary cortex (phelloderm) on its inner side, not on the outer side.
Q2 — Secondary Growth · medium · theory
Select the correct pair (Level-I).
A. Cells of medullary rays that form part of cambial ring – Interfascicular cambium ✓ Correct
B. In dicot leaves, vascular bundles are surrounded by large thick walled cells – Conjunctive tissue
C. Large colourless empty cells in the epidermis of grass leaves – Subsidiary cells
D. Loose parenchyma cells rupturing the epidermis and forming a lens shaped opening in bark – Spongy parenchyma
Solution: Medullary ray cells that become meristematic between the vascular bundles form the interfascicular cambium of the cambial ring.
Q3 — Secondary Growth · medium · theory
Complementary cells are formed by the activity of -
A. Intra fascicular cambium
B. Phellogen ✓ Correct
C. Inter fascicular cambium
D. Vascular cambium
Solution: The cork cambium (phellogen) forms loosely arranged complementary cells that make up lenticels.
Q4 — Secondary Growth · medium · theory
Vascular cambium cuts off more -
A. Secondary cortex
B. Cork
C. Secondary xylem ✓ Correct
D. Secondary phloem
Solution: The vascular cambium generally produces much more secondary xylem than secondary phloem.
Q5 — Secondary Growth · medium · theory
In a dicot root, vascular cambium originates from
A. A portion of pericycle tissue, lying opposite to protoxylem only
B. Medullary rays
C. Both parenchymatous conjunctive tissue below phloem and pericycle opposite protoxylem ✓ Correct
D. Parenchymatous conjunctive tissue located just below phloem bundles only
Solution: In dicot roots the vascular cambium is completely secondary, arising from conjunctive tissue below the phloem and from pericycle opposite the protoxylem.
Q6 — Secondary Growth · medium · theory
Select false statement -
A. Bark is a non-technical term
B. Lenticels occur in most woody trees
C. Phellem, phellogen and phelloderm are collectively known as pericarp ✓ Correct
D. Vascular cambium and cork cambium are examples of lateral meristems
Solution: Phellem, phellogen and phelloderm are collectively called periderm, not pericarp.
Q7 — Secondary Growth · medium · theory
How many of the following meristems are completely secondary in origin? A. Cork cambium of a dicot stem B. Vascular cambium of a dicot stem C. Cork cambium of a dicot root D. Vascular cambium of a dicot root
A. 4
B. 3 ✓ Correct
C. 1
D. 2
Solution: Cork cambium of stem and root and vascular cambium of root are completely secondary; the dicot stem vascular cambium is partly primary (fascicular part), so three are completely secondary.
Q8 — Secondary Growth · medium · theory
Interfascicular cambium and cork cambium are secondary meristems because
A. They appear early in the life of a plant and contribute to the formation of the secondary plant body.
B. They appear early in the life of a plant and contribute to the formation of the primary plant body.
C. They appear later than primary meristem and are responsible for producing the primary tissues
D. They appear later than primary meristem and are responsible for producing the secondary tissues ✓ Correct
Solution: Secondary meristems arise later than primary meristems and produce secondary tissues.
Q9 — Secondary Growth · easy · theory
Thickness of stem increases due to activity of :-
A. Xylem
B. Phloem
C. Shoot apex
D. Cambium ✓ Correct
Solution: The lateral meristem (cambium) adds secondary tissues, increasing the thickness/girth of the stem.
Q10 — Secondary Growth · easy · theory
Which one increases due to cambium :
A. Length
B. None
C. Circumference ✓ Correct
D. Width
Solution: The cambium adds secondary tissues laterally, increasing the girth/circumference of the axis.
Q11 — Secondary Growth · medium · theory
Function of cork cambium is to produce :-
A. Secondary xylem & secondary phloem
B. Cork & secondary cortex ✓ Correct
C. Secondary phloem & secondary cortex
D. Cork only
Solution: Cork cambium (phellogen) produces cork (phellem) on the outer side and secondary cortex (phelloderm) on the inner side.
Q12 — Secondary Growth · medium · theory
Assertion (A): During secondary growth, the amount of secondary xylem produced is more than secondary phloem and soon forms a compact mass. Reason (R): The vascular cambium (cambial ring) is generally more active on the inner side than on the outer side.
A. (A) is correct, but (R) is not correct.
B. Both (A) and (R) are correct, but (R) is not the correct explanation of (A).
C. Both (A) and (R) are incorrect.
D. Both (A) and (R) are correct, and (R) is the correct explanation of (A). ✓ Correct
Solution: The cambium cuts off more cells inward than outward, so more secondary xylem than phloem is formed; R correctly explains A.
Q13 — Secondary Growth · medium · theory
Assertion (A): Monocotyledonous and dicotyledonous plants show marked variation in their internal structures. They differ in type, number and location of vascular bundles. Reason (R): The secondary growth occurs in most of the dicotyledonous roots and stems and it increases the girth (diameter) of the organs by the activity of the vascular cambium and the cork cambium.
A. Both (A) and (R) are correct, and (R) is the correct explanation of (A).
B. Both (A) and (R) are correct, but (R) is not the correct explanation of (A). ✓ Correct
C. Both (A) and (R) are incorrect.
D. (A) is correct, but (R) is not correct.
Solution: Both are true, but the primary structural differences in A are not caused by the secondary growth described in R.
Q14 — Secondary Growth · medium · theory
Assertion (A): There are different types of wood on the basis of their composition and time of production. Reason (R): The wood is actually a secondary xylem.
A. (A) is correct, but (R) is not correct.
B. Both (A) and (R) are correct, and (R) is the correct explanation of (A).
C. Both (A) and (R) are correct, but (R) is not the correct explanation of (A). ✓ Correct
D. Both (A) and (R) are incorrect.
Solution: Both are true, but merely stating wood is secondary xylem (R) does not explain the classification of wood types in A.
Q15 — Secondary Growth · medium · theory
Statement-1: The heart wood is more durable and resistant to the attack of the microorganisms and insects as compared to the sap wood. Statement-2: The heart wood contains organic compounds like oils, aromatic substances, gums, resin, tannins and phenol etc.
A. Statement-1 is false, Statement-2 is true.
B. Statement-1 is true, Statement-2 is true; Statement-2 is the correct explanation of Statement-1. ✓ Correct
C. Statement-1 is true, Statement-2 is false.
D. Statement-1 is true, Statement-2 is true; Statement-2 is not the correct explanation of Statement-1.
Solution: The tannins, resins and phenols deposited in heartwood make it durable and resistant to decay, so Statement-2 explains Statement-1.
Q16 — Secondary Growth · medium · theory
Statement I: Monocotyledonous plants do not form secondary tissues. Statement II: In the monocotyledons, the vascular bundles have no cambium present in them.
A. Statement I is false, but statement II is true.
B. Both statement I and statement II are false.
C. Statement I is true, but statement II is false.
D. Both statement I and statement II are true. ✓ Correct
Solution: Monocot vascular bundles are closed (no cambium), so they cannot undergo secondary growth; both statements are true.
Q17 — Secondary Growth · medium · theory
Statement I: The heartwood does not conduct water but it gives mechanical support to the stem. Statement II: The central ground of the secondary xylem is lighter in colour and is known as the sapwood.
A. Both statement I and statement II are false.
B. Both statement I and statement II are true.
C. Statement I is true, but statement II is false. ✓ Correct
D. Statement I is false, but statement II is true.
Solution: Heartwood is non-conducting but supportive (I true); however the central darker region is heartwood, while sapwood is the lighter peripheral zone (II false).
Q18 — Secondary Growth · medium · theory
Heart wood differs from sapwood in
A. Being susceptible to pests and pathogens
B. Absence of vessels and parenchyma
C. Having dead and non-conducting elements ✓ Correct
D. Presence of rays and fibres
Solution: Heartwood consists of dead, non-conducting, highly lignified elements that give mechanical support, unlike the conducting sapwood.
Q19 — Secondary Growth · medium · theory
The vascular cambium normally gives rise to
A. Primary phloem
B. Phelloderm
C. Periderm
D. Secondary xylem ✓ Correct
Solution: Vascular cambium produces secondary xylem (inside) and secondary phloem (outside); periderm and phelloderm come from cork cambium.
Q20 — Secondary Growth · medium · theory
Which of the following is made up of dead cells?
A. Phloem
B. Collenchyma
C. Phellem ✓ Correct
D. Xylem parenchyma
Solution: Phellem (cork) is composed of dead, suberised cells; the others are living tissues.
Q21 — Secondary Growth · medium · theory
Identify the wrong statement in context of heartwood.
A. Organic compounds are deposited in it.
B. It comprises dead elements with highly lignified walls.
C. It conducts water and minerals efficiently. ✓ Correct
D. It is highly durable.
Solution: Heartwood does not conduct water and minerals; conduction is carried out by the sapwood.
Q22 — Secondary Growth · medium · theory
Secondary xylem and phloem in dicot stem are produced by
A. Phellogen
B. Apical meristems
C. Vascular cambium ✓ Correct
D. Axillary meristems
Solution: The vascular cambium produces secondary xylem inwards and secondary phloem outwards.
Q23 — Secondary Growth · medium · theory
Plants having little or no secondary growth are
A. Cycads
B. Conifers
C. Deciduous angiosperms
D. Grasses ✓ Correct
Solution: Grasses are monocots with closed vascular bundles lacking cambium, so they show little or no secondary growth.
Q24 — Secondary Growth · medium · theory
Which of the statements given below is not true about formation of annual rings in trees?
A. Annual rings are not prominent in trees of temperate region ✓ Correct
B. Annual ring is a combination of spring wood and autumn wood produced in a year
C. Activity of cambium depends upon variation in climate
D. Differential activity of cambium caused light and dark bands of tissue - early and late wood respectively
Solution: Annual rings are actually prominent (well marked) in temperate trees due to sharp seasonal climate changes; hence this statement is untrue.
Q25 — Secondary Growth · medium · theory
Identify the incorrect statement.
A. Sapwood is involved in conduction of water and minerals from root to leaf
B. Due to deposition of tannins, resins, oils etc. heartwood is dark in colour.
C. Sapwood is the innermost secondary xylem and is lighter in colour ✓ Correct
D. Heartwood does not conduct water but gives mechanical support.
Solution: Sapwood is the peripheral (outer), not innermost, region of secondary xylem; heartwood is the innermost. Hence the statement is incorrect.
Q26 — Secondary Growth · medium · theory
Match List-I with 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.
A. (a)-(iii), (b)-(i), (c)-(iv), (d)-(ii) ✓ Correct
B. (a)-(iv), (b)-(i), (c)-(iii), (d)-(ii)
C. (a)-(iv), (b)-(ii), (c)-(i), (d)-(iii)
D. (a)-(ii), (b)-(iii), (c)-(iv), (d)-(i)
Solution: Lenticels allow exchange of gases, cork cambium is phellogen, secondary cortex is phelloderm, and cork has suberin deposition.
Q27 — Secondary Growth · medium · theory
In old trees the greater part of secondary xylem is dark brown and resistant to insect attack due to: a. secretion of secondary metabolites 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.
A. (c) and (d) only
B. (a) and (b) only ✓ Correct
C. (b) and (d) only
D. (d) and (e) only
Solution: Heartwood becomes dark and durable due to secretion of secondary metabolites into vessel lumina and deposition of tannins/resins in the central layers of the stem.
Q28 — Secondary Growth · medium · theory
The anatomy of springwood shows some peculiar features. Identify the correct set of statements about springwood: a. It is also called earlywood; b. In spring season cambium produces xylem elements with narrow vessels; c. It is lighter in colour; d. The springwood along with autumnwood shows alternate concentric rings forming annual rings; e. It has lower density. Choose the correct answer.
A. (c), (d) and (e) only
B. (a), (b) and (d) only
C. (a), (c), (d) and (e) only ✓ Correct
D. (a), (b), (d) and (e) only
Solution: Springwood (earlywood) is lighter, less dense and forms annual rings with autumnwood; statement b is wrong because springwood has wider (not narrow) vessels.
Q29 — Secondary Growth · medium · theory
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.
A. A is false, but R is true.
B. Both A and R are true, and R is the correct explanation of A. ✓ Correct
C. A is true, but R is false.
D. Both A and R are true, but R is NOT the correct explanation of A.
Solution: Reduced cambial activity in winter produces late wood with fewer, narrow xylary elements, so R correctly explains A.
Q30 — Secondary Growth · medium · theory
Identify the correct statements: A. Lenticels are the lens-shaped openings permitting the exchange of gases. B. Bark formed early in the season is called hard bark. C. Bark is a technical term that refers to all tissues exterior to vascular cambium. D. Bark refers to periderm and secondary phloem. E. Phellogen is single layered in thickness. Choose the correct answer.
A. A, B and D only
B. A and D only ✓ Correct
C. B and C only
D. B, C and E only
Solution: Lenticels are lens-shaped gas-exchange openings (A) and bark comprises periderm plus secondary phloem (D); bark formed early is soft bark, 'bark' is a non-technical term, and phellogen is a couple of layers thick, so B, C, E are wrong.