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Biology · Class 12 Science

Nagaland Nbse Class 12 Biology — Real Previous-Year Papers

with complete answers

Real previous-year board papers, year by year — the official exam pattern, the full question paper, and every question solved the concept-first way. Distinct from the chapter-wise textbook bank.

2016–2025
Years of papers
10
Total Papers
10
Real Board Papers
0
Sample papers
284
Real-paper Q & A
0
Sample-paper Q & A

Real board-paper questions available, by year

30 Q2025complete
30 Q2024complete
28 Q2023complete
28 Q2022complete
28 Q2021complete
28 Q2020complete
28 Q2019complete
28 Q2018complete
28 Q2017complete
28 Q2016complete

Nagaland Board of School Education 2025 · Set ANNUAL

Real board examination

About this paper

The real Class-12 board examination held in 2025. Every question below is solved the concept-first way. Sample papers are labelled honestly — never shown as a past exam.

Total marks
70
Questions
30
Duration
180 min
Sections
8

The marks / questions / duration above are the official exam pattern. We currently have 30 of this paper’s questions (100% of the full paper), with 30 fully solved. Questions we couldn’t yet extract or verify are held — never shown as complete.

Sections & marks

SectionTypeQuestionsMarks eachTotal
ASection Acompulsory515
ASection Acompulsory428
ASection Acompulsory4312
ASection Acompulsory2510
BSection Bcompulsory515
BSection Bcompulsory428
BSection Bcompulsory4312
BSection Bcompulsory2510
Total3070

The question paper

The questions we hold for this paper, laid out by section. Solutions are on the Answers tab.

Board Examination

Biology

Nagaland Board of School Education 2025 · Set ANNUAL

Series/Set: ANNUALRoll No. ________
Time Allowed: 3 hoursMaximum Marks: 70

General Instructions

  1. This question paper contains 30 questions divided into 8 sections — A, A, A, A, B, B, B, B.
  2. Section A comprises 5 questions of 1 mark each (compulsory).
  3. Section A comprises 4 questions of 2 marks each (compulsory).
  4. Section A comprises 4 questions of 3 marks each (compulsory).
  5. Section A comprises 2 questions of 5 marks each (compulsory).
  6. Section B comprises 5 questions of 1 mark each (compulsory).
  7. Section B comprises 4 questions of 2 marks each (compulsory).
  8. Section B comprises 4 questions of 3 marks each (compulsory).
  9. Section B comprises 2 questions of 5 marks each (compulsory).

Above is the official exam pattern. The questions printed below are those we currently hold for this paper.

Section A

compulsory · 1 mark each · 15 of 5 shown

Q1.
A typical angiosperm anther is dithecous which means that it is
  • (a) one lobed and the lobe has one theca
  • (b) two lobed and each lobe has two theca
  • (c) one lobed and the lobe has two theca
  • (d) two lobed and each lobe has one theca
[1]
Q2.
The first restriction endonuclease isolated was
  • (a) Hind I
  • (b) Hind II
  • (c) Sal I
  • (d) Eco RI
[1]
Q3.
Match the process in column I with their uses in column II and choose the correct option: Column I \tColumn II A) ELISA \ti) Direct introduction of rDNA B) PCR \tii) Gene amplification C) Biolistic \tiii) Antigen-antibody interaction D) Micro-injection \tiv) Gold coated DNA
  • (a) A(iv), B(iii), C(ii), D(i)
  • (b) A(i), B(ii), C(iii), D(iv)
  • (c) A(ii), B(i), C(iv), D(iii)
  • (d) A(iii), B(ii), C(iv), D(i)
[1]
Q4.
In the equation, GPP-R=NPP, R represents
  • (a) Respiration losses
  • (b) Radiant energy
  • (c) Reasoning
  • (d) Recycling
[1]
Q5.
The relation between species richness and area for a wide variety of taxa on a logarithmic scale is a
  • (a) Rectangular hyperbola
  • (b) Straight line
  • (c) Sigmoid curve
  • (d) Sine curve
[1]
Q6.
"Pollen-pistil interaction is a dynamic process involving pollen recognition followed by promotion or inhibition of the pollen". Give reasons.
[2]
Page 1 of 17
Q7.
State the difference between chasmogamous flowers and cleistogamous flowers.
[2]
Q8.
Who first identified DNA as an acidic substance? What was it called then?
[2]
Q9.
Define palindromic nucleotide sequence and provide an example. **OR** Give a short description on downstream processing.
[2]
Q10.
Label the following parts on the anatropous ovule diagram. (6 labels A-F x ½ mark = 3) **OR** Label the following parts on the structure of a young anther. (6 labels A-F x ½ mark = 3)
[3]
Q11.
Mention three criteria that a molecule must fulfill to act as a genetic material. **OR** Write the techniques involved in DNA fingerprinting.
[3]
Q12.
How is separation and isolation of DNA fragments carried out in recombinant DNA technology?
[3]
Q13.
Differentiate between primary productivity and secondary productivity.
[3]
Page 2 of 17
Q14.
What is transcription? Explain the steps in the process of transcription. **OR** Explain the experimental proof on semi-conservative nature of DNA replication.
[5]
Q15.
Define biodiversity. Explain the key components of 'the evil quartet' that contribute to biodiversity loss. **OR** What happens to species diversity as we move from equator towards the pole? Explain, why tropical regions support a higher level of biodiversity than temperate or polar regions?
[5]
Section A

compulsory · 1 mark each · 15 of 5 shown

Q1.
A typical angiosperm anther is dithecous which means that it is (a) one lobed and the lobe has one theca (b) two lobed and each lobe has two theca (c) one lobed and the lobe has two theca (d) two lobed and each lobe has one theca
[1]
Q2.
The first restriction endonuclease isolated was (a) Hind I (b) Hind II (c) Sal I (d) Eco RI
[1]
Q3.
Match the process in column I with their uses in column II and choose the correct option: Column I Column II A) ELISA i) Direct introduction of rDNA B) PCR ii) Gene amplification C) Biolistic iii) Antigen-antibody interaction D) Micro-injection iv) Gold coated DNA (a) A(iv), B(iii), C(ii), D(i) (b) A(i), B(ii), C(iii), D(iv) (c) A(ii), B(i), C(iv), D(iii) (d) A(iii), B(ii), C(iv), D(i)
[1]
Q4.
In the equation, GPP-R=NPP, R represents (a) Respiration losses (b) Radiant energy (c) Reasoning (d) Recycling
[1]
Q5.
The relation between species richness and area for a wide variety of taxa on a logarithmic scale is a (a) Rectangular hyperbola (b) Straight line (c) Sigmoid curve (d) Sine curve
[1]
Page 3 of 17
Q6.
"Pollen-pistil interaction is a dynamic process involving pollen recognition followed by promotion or inhibition of the pollen". Give reasons.
[2]
Q7.
State the difference between chasmogamous flowers and cleistogamous flowers.
[2]
Q8.
Who first identified DNA as an acidic substance? What was it called then?
[2]
Q9.
Define palindromic nucleotide sequence and provide an example. **OR** Give a short description on downstream processing.
[2]
Q10.
Label the following parts on the anatropous ovule diagram. (6 labels A-F x ½ mark = 3) **OR** Label the following parts on the structure of a young anther. (6 labels A-F x ½ mark = 3)
[3]
Q11.
Mention three criteria that a molecule must fulfill to act as a genetic material. **OR** Write the techniques involved in DNA fingerprinting.
[3]
Q12.
How is separation and isolation of DNA fragments carried out in recombinant DNA technology?
[3]
Q13.
Differentiate between primary productivity and secondary productivity.
[3]
Page 4 of 17
Q14.
What is transcription? Explain the steps in the process of transcription. **OR** Explain the experimental proof on semi-conservative nature of DNA replication.
[5]
Q15.
Define biodiversity. Explain the key components of 'the evil quartet' that contribute to biodiversity loss. **OR** What happens to species diversity as we move from equator towards the pole? Explain, why tropical regions support a higher level of biodiversity than temperate or polar regions?
[5]
Section A

compulsory · 1 mark each · 15 of 5 shown

Q1.
A typical angiosperm anther is dithecous which means that it is (a) one lobed and the lobe has one theca (b) two lobed and each lobe has two theca (c) one lobed and the lobe has two theca (d) two lobed and each lobe has one theca
[1]
Q2.
The first restriction endonuclease isolated was (a) Hind I (b) Hind II (c) Sal I (d) Eco RI
[1]
Q3.
Match the process in column I with their uses in column II and choose the correct option: Column I Column II A) ELISA i) Direct introduction of rDNA B) PCR ii) Gene amplification C) Biolistic iii) Antigen-antibody interaction D) Micro-injection iv) Gold coated DNA (a) A(iv), B(iii), C(ii), D(i) (b) A(i), B(ii), C(iii), D(iv) (c) A(ii), B(i), C(iv), D(iii) (d) A(iii), B(ii), C(iv), D(i)
[1]
Q4.
In the equation, GPP-R=NPP, R represents (a) Respiration losses (b) Radiant energy (c) Reasoning (d) Recycling
[1]
Q5.
The relation between species richness and area for a wide variety of taxa on a logarithmic scale is a (a) Rectangular hyperbola (b) Straight line (c) Sigmoid curve (d) Sine curve
[1]
Page 5 of 17
Q6.
"Pollen-pistil interaction is a dynamic process involving pollen recognition followed by promotion or inhibition of the pollen". Give reasons.
[2]
Q7.
State the difference between chasmogamous flowers and cleistogamous flowers.
[2]
Q8.
Who first identified DNA as an acidic substance? What was it called then?
[2]
Q9.
Define palindromic nucleotide sequence and provide an example. **OR** Give a short description on downstream processing.
[2]
Q10.
Label the following parts on the anatropous ovule diagram. (6 labels A-F x ½ mark = 3) **OR** Label the following parts on the structure of a young anther. (6 labels A-F x ½ mark = 3)
[3]
Q11.
Mention three criteria that a molecule must fulfill to act as a genetic material. **OR** Write the techniques involved in DNA fingerprinting.
[3]
Q12.
How is separation and isolation of DNA fragments carried out in recombinant DNA technology?
[3]
Q13.
Differentiate between primary productivity and secondary productivity.
[3]
Page 6 of 17
Q14.
What is transcription? Explain the steps in the process of transcription. **OR** Explain the experimental proof on semi-conservative nature of DNA replication.
[5]
Q15.
Define biodiversity. Explain the key components of 'the evil quartet' that contribute to biodiversity loss. **OR** What happens to species diversity as we move from equator towards the pole? Explain, why tropical regions support a higher level of biodiversity than temperate or polar regions?
[5]
Section A

compulsory · 1 mark each · 15 of 5 shown

Q1.
A typical angiosperm anther is dithecous which means that it is (a) one lobed and the lobe has one theca (b) two lobed and each lobe has two theca (c) one lobed and the lobe has two theca (d) two lobed and each lobe has one theca
[1]
Q2.
The first restriction endonuclease isolated was (a) Hind I (b) Hind II (c) Sal I (d) Eco RI
[1]
Q3.
Match the process in column I with their uses in column II and choose the correct option: Column I Column II A) ELISA i) Direct introduction of rDNA B) PCR ii) Gene amplification C) Biolistic iii) Antigen-antibody interaction D) Micro-injection iv) Gold coated DNA (a) A(iv), B(iii), C(ii), D(i) (b) A(i), B(ii), C(iii), D(iv) (c) A(ii), B(i), C(iv), D(iii) (d) A(iii), B(ii), C(iv), D(i)
[1]
Q4.
In the equation, GPP-R=NPP, R represents (a) Respiration losses (b) Radiant energy (c) Reasoning (d) Recycling
[1]
Q5.
The relation between species richness and area for a wide variety of taxa on a logarithmic scale is a (a) Rectangular hyperbola (b) Straight line (c) Sigmoid curve (d) Sine curve
[1]
Page 7 of 17
Q6.
"Pollen-pistil interaction is a dynamic process involving pollen recognition followed by promotion or inhibition of the pollen". Give reasons.
[2]
Q7.
State the difference between chasmogamous flowers and cleistogamous flowers.
[2]
Q8.
Who first identified DNA as an acidic substance? What was it called then?
[2]
Q9.
Define palindromic nucleotide sequence and provide an example. **OR** Give a short description on downstream processing.
[2]
Q10.
Label the following parts on the anatropous ovule diagram. (6 labels A-F x ½ mark = 3) **OR** Label the following parts on the structure of a young anther. (6 labels A-F x ½ mark = 3)
[3]
Q11.
Mention three criteria that a molecule must fulfill to act as a genetic material. **OR** Write the techniques involved in DNA fingerprinting.
[3]
Q12.
How is separation and isolation of DNA fragments carried out in recombinant DNA technology?
[3]
Q13.
Differentiate between primary productivity and secondary productivity.
[3]
Page 8 of 17
Q14.
What is transcription? Explain the steps in the process of transcription. **OR** Explain the experimental proof on semi-conservative nature of DNA replication.
[5]
Q15.
Define biodiversity. Explain the key components of 'the evil quartet' that contribute to biodiversity loss. **OR** What happens to species diversity as we move from equator towards the pole? Explain, why tropical regions support a higher level of biodiversity than temperate or polar regions?
[5]
Section B

compulsory · 1 mark each · 15 of 5 shown

Q1.
Hormones secreted by the placenta to maintain pregnancy are (a) HCG, HPL, progesterone, prolactin (b) HCG, HPL, estrogens, relaxin (c) HCG, HPL, estrogens, progesterone (d) HCG, progesterone, estrogen, glucocorticoids
[1]
Q2.
Assertion(A): Adaptive radiation led to evolution of many varieties of finches. Reason(R): Originally finches were seed eaters. (a) Both (A) and (R) are true and (R) is the correct explanation of (A) (b) Both (A) and (R) are true but (R) is not the correct explanation of (A) (c) (A) is true but (R) is false (d) Both (A) and (R) are false
[1]
Q3.
Virus-infected cells secrete proteins called interferons which protect non-infected cells from further viral infection is called (a) cellular barrier (b) physiological barrier (c) physical barrier (d) cytokine barrier
[1]
Q4.
A compound which is produced by an organism that can kill or retard the growth of other organism is called (a) xenobiotic (b) antibiotic (c) antibody (d) probiotic
[1]
Page 9 of 17
Q5.
The first clinical application of gene therapy over a 4 year old girl was for (a) Adenosine deaminase deficiency (b) Adenosine deficiency (c) Growth deficiency (d) Adenine deficiency
[1]
Q6.
What is foetal ejection reflex and what does it trigger? **OR** What are STIs? Write two early symptoms of the disease.
[2]
Q7.
Define incomplete dominance and provide an example.
[2]
Q8.
How are genetically modified organisms (GMO) better than its wild gene?
[2]
Q9.
Expand GEAC. What is the purpose of GEAC?
[2]
Q10.
Give a comparison between the behaviour of chromosomes and genes according to Mendel. **OR** How did natural selection affect the population of moth (in England)? Briefly explain.
[3]
Q11.
What is immunity? How is active immunity different from passive immunity?
[3]
Q12.
What are methanogens? Write a short note on biogas plant.
[3]
Page 10 of 17
Q13.
State Gause's 'Competitive Exclusion Principle'. Give two examples of competition in nature. **OR** What is mutualism? Briefly explain mutualism with the wasp and fig plant interaction.
[3]
Q14.
What is an ideal contraceptive? Explain the natural and surgical method of birth control. **OR** What is the reproductive cycle in human female called? Explain the process in detail.
[5]
Q15.
Explain Mendel's third law of inheritance with the help of a dihybrid cross. **OR** Explain the primitive earth condition. Write any two theories related with the origin of life.
[5]
Section B

compulsory · 1 mark each · 15 of 5 shown

Q1.
Hormones secreted by the placenta to maintain pregnancy are (a) HCG, HPL, progesterone, prolactin (b) HCG, HPL, estrogens, relaxin (c) HCG, HPL, estrogens, progesterone (d) HCG, progesterone, estrogen, glucocorticoids
[1]
Q2.
Assertion(A): Adaptive radiation led to evolution of many varieties of finches. Reason(R): Originally finches were seed eaters. (a) Both (A) and (R) are true and (R) is the correct explanation of (A) (b) Both (A) and (R) are true but (R) is not the correct explanation of (A) (c) (A) is true but (R) is false (d) Both (A) and (R) are false
[1]
Q3.
Virus-infected cells secrete proteins called interferons which protect non-infected cells from further viral infection is called (a) cellular barrier (b) physiological barrier (c) physical barrier (d) cytokine barrier
[1]
Page 11 of 17
Q4.
A compound which is produced by an organism that can kill or retard the growth of other organism is called (a) xenobiotic (b) antibiotic (c) antibody (d) probiotic
[1]
Q5.
The first clinical application of gene therapy over a 4 year old girl was for (a) Adenosine deaminase deficiency (b) Adenosine deficiency (c) Growth deficiency (d) Adenine deficiency
[1]
Q6.
What is foetal ejection reflex and what does it trigger? **OR** What are STIs? Write two early symptoms of the disease.
[2]
Q7.
Define incomplete dominance and provide an example.
[2]
Q8.
How are genetically modified organisms (GMO) better than its wild gene?
[2]
Q9.
Expand GEAC. What is the purpose of GEAC?
[2]
Q10.
Give a comparison between the behaviour of chromosomes and genes according to Mendel. **OR** How did natural selection affect the population of moth (in England)? Briefly explain.
[3]
Q11.
What is immunity? How is active immunity different from passive immunity?
[3]
Page 12 of 17
Q12.
What are methanogens? Write a short note on biogas plant.
[3]
Q13.
State Gause's 'Competitive Exclusion Principle'. Give two examples of competition in nature. **OR** What is mutualism? Briefly explain mutualism with the wasp and fig plant interaction.
[3]
Q14.
What is an ideal contraceptive? Explain the natural and surgical method of birth control. **OR** What is the reproductive cycle in human female called? Explain the process in detail.
[5]
Q15.
Explain Mendel's third law of inheritance with the help of a dihybrid cross. **OR** Explain the primitive earth condition. Write any two theories related with the origin of life.
[5]
Section B

compulsory · 1 mark each · 15 of 5 shown

Q1.
Hormones secreted by the placenta to maintain pregnancy are (a) HCG, HPL, progesterone, prolactin (b) HCG, HPL, estrogens, relaxin (c) HCG, HPL, estrogens, progesterone (d) HCG, progesterone, estrogen, glucocorticoids
[1]
Q2.
Assertion(A): Adaptive radiation led to evolution of many varieties of finches. Reason(R): Originally finches were seed eaters. (a) Both (A) and (R) are true and (R) is the correct explanation of (A) (b) Both (A) and (R) are true but (R) is not the correct explanation of (A) (c) (A) is true but (R) is false (d) Both (A) and (R) are false
[1]
Page 13 of 17
Q3.
Virus-infected cells secrete proteins called interferons which protect non-infected cells from further viral infection is called (a) cellular barrier (b) physiological barrier (c) physical barrier (d) cytokine barrier
[1]
Q4.
A compound which is produced by an organism that can kill or retard the growth of other organism is called (a) xenobiotic (b) antibiotic (c) antibody (d) probiotic
[1]
Q5.
The first clinical application of gene therapy over a 4 year old girl was for (a) Adenosine deaminase deficiency (b) Adenosine deficiency (c) Growth deficiency (d) Adenine deficiency
[1]
Q6.
What is foetal ejection reflex and what does it trigger? **OR** What are STIs? Write two early symptoms of the disease.
[2]
Q7.
Define incomplete dominance and provide an example.
[2]
Q8.
How are genetically modified organisms (GMO) better than its wild gene?
[2]
Q9.
Expand GEAC. What is the purpose of GEAC?
[2]
Q10.
Give a comparison between the behaviour of chromosomes and genes according to Mendel. **OR** How did natural selection affect the population of moth (in England)? Briefly explain.
[3]
Page 14 of 17
Q11.
What is immunity? How is active immunity different from passive immunity?
[3]
Q12.
What are methanogens? Write a short note on biogas plant.
[3]
Q13.
State Gause's 'Competitive Exclusion Principle'. Give two examples of competition in nature. **OR** What is mutualism? Briefly explain mutualism with the wasp and fig plant interaction.
[3]
Q14.
What is an ideal contraceptive? Explain the natural and surgical method of birth control. **OR** What is the reproductive cycle in human female called? Explain the process in detail.
[5]
Q15.
Explain Mendel's third law of inheritance with the help of a dihybrid cross. **OR** Explain the primitive earth condition. Write any two theories related with the origin of life.
[5]
Section B

compulsory · 1 mark each · 15 of 5 shown

Q1.
Hormones secreted by the placenta to maintain pregnancy are (a) HCG, HPL, progesterone, prolactin (b) HCG, HPL, estrogens, relaxin (c) HCG, HPL, estrogens, progesterone (d) HCG, progesterone, estrogen, glucocorticoids
[1]
Page 15 of 17
Q2.
Assertion(A): Adaptive radiation led to evolution of many varieties of finches. Reason(R): Originally finches were seed eaters. (a) Both (A) and (R) are true and (R) is the correct explanation of (A) (b) Both (A) and (R) are true but (R) is not the correct explanation of (A) (c) (A) is true but (R) is false (d) Both (A) and (R) are false
[1]
Q3.
Virus-infected cells secrete proteins called interferons which protect non-infected cells from further viral infection is called (a) cellular barrier (b) physiological barrier (c) physical barrier (d) cytokine barrier
[1]
Q4.
A compound which is produced by an organism that can kill or retard the growth of other organism is called (a) xenobiotic (b) antibiotic (c) antibody (d) probiotic
[1]
Q5.
The first clinical application of gene therapy over a 4 year old girl was for (a) Adenosine deaminase deficiency (b) Adenosine deficiency (c) Growth deficiency (d) Adenine deficiency
[1]
Q6.
What is foetal ejection reflex and what does it trigger? **OR** What are STIs? Write two early symptoms of the disease.
[2]
Q7.
Define incomplete dominance and provide an example.
[2]
Q8.
How are genetically modified organisms (GMO) better than its wild gene?
[2]
Q9.
Expand GEAC. What is the purpose of GEAC?
[2]
Page 16 of 17
Q10.
Give a comparison between the behaviour of chromosomes and genes according to Mendel. **OR** How did natural selection affect the population of moth (in England)? Briefly explain.
[3]
Q11.
What is immunity? How is active immunity different from passive immunity?
[3]
Q12.
What are methanogens? Write a short note on biogas plant.
[3]
Q13.
State Gause's 'Competitive Exclusion Principle'. Give two examples of competition in nature. **OR** What is mutualism? Briefly explain mutualism with the wasp and fig plant interaction.
[3]
Q14.
What is an ideal contraceptive? Explain the natural and surgical method of birth control. **OR** What is the reproductive cycle in human female called? Explain the process in detail.
[5]
Q15.
Explain Mendel's third law of inheritance with the help of a dihybrid cross. **OR** Explain the primitive earth condition. Write any two theories related with the origin of life.
[5]
Page 17 of 17