CUET UG Categorised PYQ Biology Unit 11 -

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CUET UG Categorised PYQ Biology Unit 11

BIOLOGY

⏱️ 30 Minutes

❓ 15 Questions

📅 2022, 2023, 2024 & 2025

✍️ Long Answers

📌 Answers are locked once submitted — results and explanations appear at the end.

CUET UG Categorised PYQ Biology Unit 11

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QUESTION 1 OF 15

Which of the following option determines percolation and water holding capacity of soils? (PYQ 2022 Shift 1)

Answer Review

1 Which of the following option determines percolation and water holding capacity of soils? (PYQ 2022 Shift 1)

A Climate

B Grain size, soil composition and aggregation

C Weathering process

D Soil development

💡 Short Explanation

Soil texture affects water movement. Aggregation influences pore spaces. Determines water retention.

✅ Correct Answer Explanation

Percolation and water-holding capacity depend mainly on grain size, soil composition and aggregation because these factors determine soil pore size and moisture retention.

❓ Why Other Options Are Incorrect

Option A) Indirect effect only.
Option C) Soil formation process.
Option D) Broad process, not direct determinant.

🎯 Strategy

Used: NCERT Recall

Option A → Indirect.
Option B → Correct.
Option C → Indirect.
Option D → Broad term.

Final Answer → Option B.

🧠 Memory Trick

📚 Class XII → Book: Biology → Chapter: Organisms and Populations → Section/Theme: Soil Factors.

2 The shape of pyramids gives the reflection of growth status of a population. Identify the growth status depicted by the given pyramid. (PYQ 2022 Shift 1)

A Expanding

B Declining

C Exploding

D Stable

💡 Short Explanation

Bell-shaped population pyramid. Similar pre-reproductive and reproductive groups. Indicates stable population.

✅ Correct Answer Explanation

A stable population shows nearly equal proportions of individuals in pre-reproductive and reproductive age groups. The population size remains relatively constant over time, producing a stable pyramid shape.

❓ Why Other Options Are Incorrect

Option A) Expanding → Broad base pyramid.
Option B) Declining → Narrow base pyramid.
Option C) Exploding → Not a standard NCERT growth status category.

🎯 Strategy

Used: Diagram Identification

Option A → Expanding shape differs.
Option B → Declining shape differs.
Option C → Not standard.
Option D → Correct.

Final Answer → Stable.

🧠 Memory Trick

📚 Class XII → Book: Biology → Chapter: Organisms and Populations → Section/Theme: Age Pyramids.

3 Match List – I with List – II (PYQ 2022 Shift 1)

List – I	List – II
(A) Natality	(I) Number of individuals coming into the habitat from elsewhere
(B) Mortality	(II) Number of births in the population
(C) Immigration	(III) Number of individuals leaving the habitat
(D) Emigration	(IV) Number of deaths in the population

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

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

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

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

💡 Short Explanation

Natality = Births. Mortality = Deaths. Immigration = Entry. Emigration = Exit.

✅ Correct Answer Explanation

Correct matching: Natality → Number of births. Mortality → Number of deaths. Immigration → Individuals entering habitat. Emigration → Individuals leaving habitat.

❓ Why Other Options Are Incorrect

Option B) Natality and mortality reversed.
Option C) Multiple incorrect matches.
Option D) Multiple incorrect matches.

🎯 Strategy

Used: Option Grouping

Option A → Correct.
Option B → Incorrect.
Option C → Incorrect.
Option D → Incorrect.

Final Answer → Option A.

🧠 Memory Trick

📚 Class XII → Book: Biology → Chapter: Organisms and Populations → Section/Theme: Population Attributes.

4 If there were 100 rose plants last year, 20 new rose plants are added through reproduction, birth rate = ? (PYQ 2023 Shift 1)

A 0.5

B 5.0

C 0.02

D 0.2

💡 Short Explanation

Birth rate = Births ÷ Initial population. 20 ÷ 100 = 0.2. Expressed per individual.

✅ Correct Answer Explanation

Birth rate (b) is calculated as: Birth rate = Number of births ÷ Total population = 20 ÷ 100 = 0.2 Thus, the birth rate is 0.2.

❓ Why Other Options Are Incorrect

Option A) 0.5 → Incorrect calculation.
Option B) 5.0 → Opposite ratio.
Option C) 0.02 → Decimal place error.

🎯 Strategy

Used: Substitution

Option A → Arithmetic error.
Option B → Incorrect ratio.
Option C → Decimal mistake.
Option D → Correct calculation.

Final Answer → 0.2.

🧠 Memory Trick

📚 Class XII → Book: Biology → Chapter: Organisms and Populations → Section/Theme: Population Growth Attributes.

5 Select the organisms which breed once in their lifetime: (PYQ 2023 Shift 1)
(A) Squirrel
(B) House sparrow
(C) Pacific salmon
(D) Bamboo

A (A) and (B) only

B (B) and (C) only

C (B) and (D) only

D (C) and (D) only

💡 Short Explanation

Pacific salmon breeds once. Bamboo flowers once and dies. Called semelparous organisms.

✅ Correct Answer Explanation

Semelparous organisms reproduce only once in their lifetime. Pacific salmon reproduces once before death. Bamboo species flower once after many years and die afterward. Squirrels and sparrows reproduce multiple times.

❓ Why Other Options Are Incorrect

Option A) Squirrel and sparrow are iteroparous.
Option B) House sparrow breeds multiple times.
Option C) House sparrow is not semelparous.

🎯 Strategy

Used: NCERT Recall

Option A → Incorrect.
Option B → House sparrow wrong.
Option C → House sparrow wrong.
Option D → Both semelparous.

Final Answer → Option D.

🧠 Memory Trick

📚 Class XII → Book: Biology → Chapter: Organisms and Populations → Section/Theme: Life History Variations.

6 Match List I with List II (PYQ 2023 Shift 2)

List I	List II
A. Cuckoo lays egg in crow's nest	I. Commensalism
B. Orchid grows in mango tree	II. Parasitism
C. Ticks live on skin of dogs	III. Mutualism
D. Species of Wasp and fig species	IV. Brood parasitism

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

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

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

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

💡 Short Explanation

Cuckoo → Brood parasitism. Orchid → Commensalism. Tick → Parasitism. Wasp-Fig → Mutualism.

✅ Correct Answer Explanation

Cuckoo exploits crow's nest and parental care (brood parasitism). Orchid uses mango tree for support without harming it (commensalism). Ticks obtain nutrition from dogs (parasitism). Fig and fig wasp benefit each other (mutualism).

❓ Why Other Options Are Incorrect

Option A) Tick and wasp relationships mismatched.
Option C) Tick incorrectly matched with mutualism.
Option D) Multiple relationships mismatched.

🎯 Strategy

Used: Option Grouping

Option A → Incorrect.
Option B → Correct.
Option C → Incorrect.
Option D → Incorrect.

Final Answer → Option B.

🧠 Memory Trick

📚 Class XII → Book: Biology → Chapter: Organisms and Populations → Section/Theme: Population Interactions.

7 Which of the following equation is correct about Verhulst-Pearl Logistic Growth? (PYQ 2024 Shift 1, 2024 Shift 2)

A dN/dt = (h − d)(K − N)/K

B dN/dt = rN(N − K)/K

C dN/dt = rN(K − N)/K

D dN/dt = (h − d)(N − K)/N

💡 Short Explanation

Logistic growth includes carrying capacity (K). Population growth slows near K. Standard Verhulst-Pearl equation.

✅ Correct Answer Explanation

The Verhulst-Pearl logistic growth equation is: where: • N = population size • r = intrinsic rate of natural increase • K = carrying capacity As N approaches K, growth rate decreases and eventually becomes zero.

❓ Why Other Options Are Incorrect

Option A) Missing population size term (N).
Option B) Sign is reversed, giving biologically incorrect growth.
Option D) Incorrect formulation.

🎯 Strategy

Used: Formula Recall

Option A → Incomplete equation.
Option B → Wrong sign.
Option C → Correct logistic equation.
Option D → Incorrect formula.

Final Answer → Formula Recall.

🧠 Memory Trick

📚 Class XII → Book: Biology → Chapter: Organisms and Populations → Section/Theme: Population Growth Models.

8 In a laboratory, if 50 Drosophila out of a population of 250 die in a week then the death rate is ______ individual per Drosophila per week. (PYQ 2023 Shift 3)

A 0.2

B 2.0

C 5.0

D 0.5

💡 Short Explanation

Death rate = Number died ÷ Total population. 50 ÷ 250 = 0.2. Expressed per individual per week.

✅ Correct Answer Explanation

Death rate (d) = Number of deaths ÷ Total population. d = 50 ÷ 250 = 0.2 Therefore, the death rate is 0.2 individual per Drosophila per week.

❓ Why Other Options Are Incorrect

Option B) 2.0 → Ten times larger than actual value.
Option C) 5.0 → Incorrect calculation.
Option D) 0.5 → Does not match formula.

🎯 Strategy

Used: Substitution

Option A → Correct calculation.
Option B → Overestimated.
Option C → Incorrect.
Option D → Incorrect.

Final Answer → 0.2.

🧠 Memory Trick

📚 Class XII → Book: Biology → Chapter: Organisms and Populations → Section/Theme: Population Growth Attributes.

9 Match List I with List II (PYQ 2023 Shift 3)

List I (Name of Interaction)	List II (Example)
A. Commensalism	I. Fig species and wasp
B. Mutualism	II. Sea anemone and clown fish
C. Competition	III. Acacia and ant
D. Parasitism	IV. Abingdon tortoise and goat in Galapagos Islands

A A–I, B–II, C–III, D–IV

B A–I, B–III, C–II, D–IV

C A–II, B–I, C–IV, D–III

D A–II, B–III, C–IV, D–I

💡 Short Explanation

Sea anemone–clown fish → Commensalism. Fig–wasp → Mutualism. Tortoise–goat → Competition. Acacia–ant → NCERT example of interaction.

✅ Correct Answer Explanation

Commensalism → Sea anemone and clown fish. Mutualism → Fig species and wasp. Competition → Abingdon tortoise and goat in Galapagos Islands. Parasitism → Acacia and ant (as per given matching options). Hence Option C gives the required pairing.

❓ Why Other Options Are Incorrect

Option A) Commensalism and mutualism mismatched.
Option B) Competition incorrectly matched.
Option D) Multiple incorrect pairings.

🎯 Strategy

Used: Option Grouping

Option A → Incorrect.
Option B → Incorrect.
Option C → Correct.
Option D → Incorrect.

Final Answer → Option C.

🧠 Memory Trick

📚 Class XII → Book: Biology → Chapter: Organisms and Populations → Section/Theme: Population Interactions.

10 The number of individuals in reproductive age group is more than pre-reproductive age group. The age pyramid reflects: (PYQ 2025 Shift 1)

A Expanding

B Stable

C Declining

D Homeostasis

💡 Short Explanation

Fewer young individuals. Population replacement decreases. Indicates future decline.

✅ Correct Answer Explanation

A declining population has fewer individuals in the pre-reproductive age group compared to the reproductive age group. This indicates that fewer individuals will enter the reproductive stage in the future, leading to a gradual decrease in population size. Such age pyramids are urn-shaped.

❓ Why Other Options Are Incorrect

Option A) Expanding → Expanding populations have a broad pre-reproductive base.
Option B) Stable → Stable populations have nearly equal pre-reproductive and reproductive groups.
Option D) Homeostasis → Not a recognized age-pyramid category.

🎯 Strategy

Used: Contextual/Tonal Matching

Option A → Growing population.
Option B → Balanced population.
Option C → Matches given condition.

Final Answer → Based on population structure.

🧠 Memory Trick

📚 Class 12 Biology → Chapter: Organisms and Populations → Section/Theme: Population Age Structure.

11 Name the population interaction which takes place when one species is benefitted and another species has no effect. (PYQ 2024 Shift 1)

A Competition

B Predation

C Commensalism

D Amensalism

💡 Short Explanation

One species benefits. Other remains unaffected. Classic +/0 interaction.

✅ Correct Answer Explanation

Commensalism is an interaction in which one species benefits while the other is neither harmed nor benefited. Example: Orchid growing on a mango tree.

❓ Why Other Options Are Incorrect

Option A) Both species are negatively affected.
Option B) One benefits, one harmed.
Option D) One harmed, other unaffected.

🎯 Strategy

Used: Contextual/Tonal Matching

Option A → −/−.
Option B → +/−.
Option C → +/0.
Option D → −/0.

Final Answer → Commensalism.

🧠 Memory Trick

📚 Class 12 Biology → Chapter: Organisms and Populations.

12 Identify the incorrect matching: (PYQ 2024 Shift 1)

A + + → Mutualism

B + – → Parasitism

C – – → Predation

D – 0 → Amensalism

💡 Short Explanation

Predation is +/−. Competition is −/−. Therefore matching is incorrect.

✅ Correct Answer Explanation

In predation, the predator benefits while the prey is harmed (+/−). A −/− interaction represents competition, where both species suffer due to resource sharing.

❓ Why Other Options Are Incorrect

Option A) Correct mutualism interaction.
Option B) Correct parasitic interaction.
Option D) Correct amensalism interaction.

🎯 Strategy

Used: Option Grouping

Option A → Correct.
Option B → Correct.
Option C → Incorrect.
Option D → Correct.

Final Answer → Option C.

🧠 Memory Trick

📚 Class 12 Biology → Chapter: Organisms and Populations.

13 Given below are two statements:
Statement I: An orchid grows as an epiphyte on a mango branch where mango tree does not derive any apparent benefit from it.
Statement II: An orchid growing on a mango tree is an example of commensalism.
(PYQ 2024 Shift 1)

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

💡 Short Explanation

Orchid benefits. Mango tree unaffected. Classic commensalism.

✅ Correct Answer Explanation

Epiphytic orchids use mango trees only for physical support. The orchid gains benefit while the mango tree remains unaffected. This is the standard NCERT example of commensalism.

❓ Why Other Options Are Incorrect

Option B) Both statements are actually true.
Option C) Statement II is true.
Option D) Statement I is also true.

🎯 Strategy

Used: Contextual/Tonal Matching

Option A → Both correct.
Option B → Incorrect.
Option C → Incorrect.
Option D → Incorrect.

Final Answer → Option A.

🧠 Memory Trick

📚 Class 12 Biology → Chapter: Organisms and Populations.

14 Match the following: (PYQ 2024 Shift 1)

List-I	List-II
A. Abingdon tortoise extinction	I. Parasitism
B. Marine fish & copepods	II. Commensalism
C. Cattle egret & cattle	III. Mutualism
D. Fig tree & wasp	IV. Competition

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

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

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

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

💡 Short Explanation

Fish–copepods = parasitism. Cattle egret–cattle = commensalism. Fig–wasp = mutualism.

✅ Correct Answer Explanation

Correct matching: Abingdon tortoise extinction → Competition. Marine fish & copepods → Parasitism. Cattle egret & cattle → Commensalism. Fig tree & wasp → Mutualism. Thus Option D is correct.

❓ Why Other Options Are Incorrect

Option A) Fish and copepods mismatched.
Option B) Multiple incorrect pairings.
Option C) Incorrect ecological relationships.

🎯 Strategy

Used: Option Grouping

Option A → Incorrect.
Option B → Incorrect.
Option C → Incorrect.
Option D → Correct.

Final Answer → Option D.

🧠 Memory Trick

📚 Class 12 Biology → Chapter: Organisms and Populations.

15 Select the incorrect pair in response to abiotic factors: (PYQ 2024 Shift 1)

A We maintain a constant body temperature of 37°C – Conformer

B Every winter Keoladeo National Park hosts the birds coming from Siberia – Migration

C Under unfavourable conditions many zooplankton species in ponds enter the stage of suspended development – Diapause

D If a predator is too efficient it overexploits its prey – Extinction

💡 Short Explanation

Humans are regulators, not conformers. Regulators maintain internal temperature. Conformers vary with environment.

✅ Correct Answer Explanation

Humans maintain a nearly constant body temperature irrespective of environmental temperature. Such organisms are called regulators. Conformers are organisms whose body temperature changes with environmental conditions.

❓ Why Other Options Are Incorrect

Option B) Correct example of migration.
Option C) Correct example of diapause.
Option D) Correct ecological principle.

🎯 Strategy

Used: Odd One Out

Option A → Incorrect pairing.
Option B → Correct pairing.
Option C → Correct pairing.
Option D → Correct pairing.

Final Answer → Humans are regulators.

🧠 Memory Trick

📚 Class 12 Biology → Chapter: Organisms and Populations.

CUET UG Categorised PYQ Biology Unit 11

Test Complete!

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