Part 8 — Advanced, Assertion-Reason & Application-based NEET-Style Questions (Questions 176–200)
Part 8 – Advanced, Assertion–Reason & Application-based NEET-Style Questions (176–200)
Q176. Assertion (A): Xylem in monocot stems does not form annual rings. Reason (R): Secondary growth is absent in most monocots.
A) Both A and R are true, and R is the correct explanation
B) Both A and R true, but R not explanation
C) A true, R false
D) Both false
Answer: A
Explanation:
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Annual rings = result of secondary growth (cambium).
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Monocots usually lack secondary growth → no rings.
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Both statements correct; R explains A.
Q177. Assertion (A): In dicot roots, xylem is exarch. Reason (R): Protoxylem is towards the periphery, metaxylem towards the center.
A) Both A and R true, R explains A
B) Both true but R not explanation
C) A false, R true
D) Both false
Answer: A
Explanation:
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Exarch condition = protoxylem near periphery, metaxylem inside.
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Correct for dicot root → Both A and R true and explanatory.
Q178. A cross-section shows scattered vascular bundles with closed cambium. The section is of:
A) Dicot stem
B) Dicot root
C) Monocot stem
D) Monocot root
Answer: C
Explanation:
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A) Dicot stem – bundles arranged in ring.
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B) Dicot root – radial vascular bundles.
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C) Correct – monocot stem has scattered, closed bundles.
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D) Monocot root – radial arrangement.
Q179. Assertion (A): Bundle sheath is present around vascular bundles in monocot leaves. Reason (R): It plays a key role in C4 photosynthesis.
A) Both A and R true, R explains A
B) Both true, but R not explanation
C) A true, R false
D) Both false
Answer: B
Explanation:
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Bundle sheath present in all monocot leaves (Kranz anatomy in C4, e.g., maize).
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But presence itself is not always for C4 function.
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So both true, but R doesn’t fully explain A.
Q180. Which tissue system forms protective covering of plant body?
A) Ground tissue
B) Dermal tissue
C) Vascular tissue
D) Meristematic tissue
Answer: B
Explanation:
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A) Ground tissue = cortex, pith.
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B) Correct – epidermis, cuticle, stomata protect plant.
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C) Vascular = conduction.
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D) Meristems = growth, not covering.
Q181. Assertion (A): Companion cells are absent in gymnosperms. Reason (R): Albuminous cells perform similar functions as companion cells.
A) Both A and R true, R explains A
B) Both A and R true, but R not explanation
C) A true, R false
D) Both false
Answer: A
Explanation:
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Gymnosperms have sieve cells (not sieve tubes) + albuminous cells.
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Companion cells are angiosperm features.
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R explains A.
Q182. A plant tissue shows loosely packed parenchyma with large air cavities. It belongs to:
A) Collenchyma
B) Sclerenchyma
C) Aerenchyma
D) Phloem
Answer: C
Explanation:
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A) Collenchyma – support.
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B) Sclerenchyma – dead, lignified.
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C) Correct – aerenchyma in hydrophytes (buoyancy).
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D) Phloem – transport, not air spaces.
Q183. Assertion (A): Pericycle gives rise to lateral roots in dicot roots. Reason (R): Pericycle is the outermost layer of stele, with meristematic ability.
A) Both A and R true, R explains A
B) Both A and R true, but R not explanation
C) A true, R false
D) Both false
Answer: A
Explanation:
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Lateral roots originate from pericycle.
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Its position and meristematic nature enable root branching.
Q184. Which condition describes phloem in dicot stem?
A) Endarch
B) Exarch
C) Centric
D) Situated external to xylem in conjoint bundles
Answer: D
Explanation:
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A/B/C) Not correct.
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D) Correct – phloem external, xylem internal in dicot stems.
Q185. Assertion (A): Endodermis acts as a selective barrier. Reason (R): Casparian strips of suberin block apoplastic flow.
A) Both A and R true, R explains A
B) Both true, but R not explanation
C) A true, R false
D) Both false
Answer: A
Explanation:
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Endodermis regulates entry into stele.
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Casparian strips force symplastic movement → selective absorption.
Q186. If you find sclerenchymatous bundle sheath around vascular bundles in leaf, it indicates:
A) Dicot leaf
B) C3 monocot leaf
C) C4 monocot leaf with Kranz anatomy
D) Gymnosperm leaf
Answer: C
Explanation:
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Kranz anatomy = bundle sheath of thick-walled cells in C4 plants.
Q187. Assertion (A): Cambium is absent in monocot stems. Reason (R): Hence secondary growth is not found in monocots.
A) Both A and R true, R explains A
B) Both A and R true, but R not explanation
C) A true, R false
D) Both false
Answer: A
Explanation:
-
Cambium absent → bundles closed → no secondary growth.
Q188. An annual ring is formed due to:
A) Alternation of primary xylem and phloem
B) Seasonal activity of vascular cambium producing early and late wood
C) Activity of cork cambium
D) Alternation of sclerenchyma and collenchyma
Answer: B
Explanation:
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Early wood (spring) + late wood (autumn) forms a ring annually.
Q189. Assertion (A): Heartwood is physiologically active. Reason (R): It stores food and water conduction occurs through it.
A) Both true, R explains A
B) Both true, R not explanation
C) A false, R true
D) Both false
Answer: D
Explanation:
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Heartwood = dead, no conduction.
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Food storage/conduction = sapwood.
Q190. Application: A stem section shows secondary xylem with large early wood vessels followed by small thick-walled late wood. This plant grew in:
A) Constant tropical climate
B) Seasonal climate with growth periods
C) Desert with no growth cycles
D) Hydroponic lab condition
Answer: B
Explanation:
-
Annual rings only in seasonal environments.
Q191. Assertion (A): Collenchyma provides flexibility. Reason (R): It has living cells with unevenly thickened walls.
A) Both A and R true, R explains A
B) Both true, but R not explanation
C) A true, R false
D) Both false
Answer: A
Explanation:
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Collenchyma = living cells, flexible, thick at corners.
Q192. Lenticels are important for:
A) Photosynthesis
B) Secondary growth
C) Gaseous exchange in woody stems
D) Water absorption
Answer: C
Explanation:
-
Lenticels = breaks in periderm for gas exchange.
Q193. Assertion (A): Guard cells contain chloroplasts. Reason (R): ATP from chloroplasts helps regulate stomatal opening.
A) Both A and R true, R explains A
B) Both true, R not explanation
C) A true, R false
D) Both false
Answer: A
Explanation:
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Guard cells uniquely have chloroplasts.
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Photosynthetic ATP helps osmotic regulation → stomata open.
Q194. In a dicot root section, xylem and phloem are arranged in:
A) Conjoint collateral bundles
B) Radial bundles with xylem and phloem alternating in different radii
C) Scattered bundles
D) Concentric bundles
Answer: B
Explanation:
-
Radial bundles typical of roots.
Q195. Assertion (A): Sapwood is lighter and physiologically active. Reason (R): It is the outer secondary xylem involved in conduction.
A) Both A and R true, R explains A
B) Both true, but R not explanation
C) A true, R false
D) Both false
Answer: A
Explanation:
-
Sapwood conducts water and food → active xylem.
Q196. Application: A student observes thick-walled cells with lignin, no protoplasm. The tissue is:
A) Parenchyma
B) Collenchyma
C) Sclerenchyma
D) Phloem
Answer: C
Explanation:
-
Sclerenchyma = dead, lignified cells.
Q197. Assertion (A): Xylem fibres are the only living cells in xylem. Reason (R): They help in water conduction.
A) Both A and R true, R explains A
B) Both true, but R not explanation
C) A false, R true
D) Both false
Answer: D
Explanation:
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Xylem fibres = dead.
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Xylem parenchyma = living, for storage, not conduction.
Q198. Application: Which plant tissue is the basis of classification into dicots and monocots in transverse sections of stems and roots?
A) Xylem type and arrangement of vascular bundles
B) Presence of epidermis
C) Presence of parenchyma
D) Presence of stomata
Answer: A
Explanation:
-
Vascular bundle arrangement distinguishes monocot vs dicot.
Q199. Assertion (A): Secondary growth in dicot stems increases girth. Reason (R): Vascular cambium forms secondary xylem inward, secondary phloem outward.
A) Both A and R true, R explains A
B) Both true, but R not explanation
C) A true, R false
D) Both false
Answer: A
Explanation:
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Cambium activity → radial growth.
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Explanation correct.
Q200. Application: You are given a woody log without leaves. By examining annual rings, you can estimate:
A) Its height
B) Its age
C) Its leaf venation pattern
D) Its family
Answer: B
Explanation:
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Annual rings count = plant’s age.