2. Which one of the following parts is not responsible for transpiration in plants?

• A) Root
• B) Stem
• C) Leaves
• D) All aerial parts

3. Which type of mutation is caused by the addition or deletion of a single nitrogenous base?

• A) Transition
• B) Transversion
• C) Frame shift
• D) Substitution

4. What basis would you apply to distinguish a meristematic tissue from a permanent tissue?

• A) Supporting plant
• B) Providing food
• C) Activating cell division
• D) Losing ability of cell division

5. Some of the C4 plants possess diagnostic features of Kranz anatomy. Select which of the following plant contains such features?

• A) Wheat
• B) Maize
• C) Barley
• D) Oats

Group ‘B’

Give short answer to the following questions. 4×4=16

6. Define vascular bundle. What type of vascular bundle is present in monocot root? Mention any two functions of vascular bundle. (1+1+2)

7. Study the given figure carefully and answer the following questions. (1+2+1)

8. If you are assigned to make a Watson and Crick model of DNA, what essential components do you apply to make the exact structure of the DNA. (2+2)

OR

Assuming you are provided seeds for germination, which influencing parameters you need to follow for normal germination? What would happen when seeds are kept in low temperature? (3+1)

9. Biotechnology is an emerging discipline in this era. Would you think can it be used to mitigate the problem of food scarcity in context to Nepal? Justify your opinion. (4)

Group ‘C’

Long answer questions. 2×8=16

10. Three German biochemists Embden, Meyerhof and Paranas (EMP) worked out a pathway which involved the formation of pyruvic acids from a glucose molecule. Identify this pathway. Name the site where this pathway takes place in a cell. Construct a step by step pathway developed by them. List the net gain of ATP in this pathway. (1+1+5+1)

11. Semi conservative mode of DNA replication is the most common mode of replication which results in two identical daughter DNA molecules. Explain various enzymes and mechanism involved during this process with necessary diagrams. (2+4+2)

“Genes are inherited in new combination due to crossing over in the gametes”. Interpret this statement with its mechanism and necessary diagrams. Assess its significance also. (4+2+2)

Section: II (Zoology)

Group ‘A’

6×1=6

12. Which of the following tissue lacks blood supply?

• A) Areolar
• B) Muscular
• C) Bone
• D) Cartilage

13. In frog, coelom is derived from which embryonic layer?

• A) Ectoderm
• B) Mesoderm
• C) Endoderm
• D) Mesogloea

14. What kind of enzyme is needed for digestion of milk protein in human beings?

• A) Rennin
• B) Lactase
• C) Pepsin
• D) Sucrase

15. Which one of the following sets contains the bacterial disease only?

• A) Hepatitis, influenza, cholera
• B) Cholera, typhoid, candidiasis
• C) Tuberculosis, typhoid, cholera
• D) Tuberculosis, cholera, candidiasis

16. If the cerebellum of a person gets injured, it will have effect on which of the following physiological function?

• A) respiratory ability.
• B) body movement
• C) memory function
• D) smelling power

17. Vas deferens transport spermatozoa from cauda epididymis to ejaculatory duct. What happens when the vas deferens of a male is surgically disconnected?

• A) Sperms become non-motile
• B) Sperms lack nuclei
• C) Seminal fluid is without sperms
• D) No spermatogenesis occurs

Group ‘B’

Give short answer to the following questions. 4×4=16

18. Define blastulation. Write down the process of blastulation during the development of frog. (1+3)

OR

What is immunity? Explain its type. (1+3)

19. Study the given figure carefully and answer the following questions. (1+1+2)

i. Identify the gland.
ii. Where is it located?
iii. Mention any two hormones secreted by it.

20. Compare and contrast areolar and adipose connective tissues. (2+2)

21. Peer pressure plays a negative role in provoking smoking habits in adolescents. As a school captain, plan any two activities you would like to organize with the help of senior students and any other two activities you would like your school authorities to organize for the students to tackle this problem. (2+2)

Group ‘C’

Give long answer to the following questions. (2×8=16)

22. Why typhoid is called enteric fever? Illustrate its causative agent, mode of transmission, symptoms and preventive measures. (1+1+2+2+2 )

23. A human being usually take complex foods in her/his diet. However, our body needs its simpler form. Describe how the complex foods are converted into simpler forms within alimentary canal. Draw it with a well labeled diagram of alimentary canal. What would happen in digestion if the gall bladder is removed surgically?(4+ 2+ 2)

OR

On oxidation of glucose in the cells, CO2 is released as a by-product. This CO2 is carried to the lungs for elimination. Explain how the transport of CO2 take place in human body? What is the role of carbonic anhydrase enzyme? Mention the significance of diaphragm in breathing? (5+1+2)

Class 12 NEB Biology Model Question Solution 2079/2080

Candidates
are required to give their answers in their own words as far as
practicable. The figures in the margin indicate full marks.

Time: 3hrs                                                                  Full Mark:75                                                                                                             

Attempt all questions.

Group “A”

1) What is an arrangement of the n natural numbers called?

• A) Induction
• B) Permutation
• C) Combination
• D) Expectation

Ans: B) Permutation

2) Let 1,w,w² be the cube roots of unity. Under which operation is the set A={1,w,w²} closed?

• A) Addition
• B) Subtraction
• C) Multiplication
• D) Division

Ans: C) Multiplication

3) What is the domain of sin^-1x?

• A) x≥1 or x≤-1
• B) (∞,infinity)
• C) -1<x<1
• D) -1≤x≤1

Ans: D) -1≤x≤1

4) ABCD is a parallelogram. Which one of the following represents area of the parallelogram?

• A) 2nπ ±2π/3
  
• B) nπ + (−1)^n π/3
  
• C) nπ −π/3
  
• D) nπ +π/3

Ans: A) 2nπ ±2π/3

7) Let A and B be two dependent events. If P (A) =1/2, P (B) = 3/4 and P(AnB) =2/5, what is the value of P(A/B)?

• A) equal to P(B/A)
• B) equal to P(A)
• C) less than P(A A B)
• D) less than P(B/A)

Ans:D) Less than P(B/A)

8) The edge of a cube increases from 10 cm to 10.025 cm. What would be the approximate increment in volume?

• A) 103 cm^3?
• B) 10.0253 cm^3?
• C) 7.5187 cm^3?
• D) 7.5 cm^3?

Ans: D) 7.5 cm^3?

9) What is the integrating factor of the differential equation cos’× dy + y =1°

• A) tan x
• B) e^tanx
• C) sec^2 x
• D)e^sec1x

Ans: B) e^tanx

10) What is the number of solutions of the system of linear equations × + y = 5 and x + y = 7?

• A) One solution
• B) No solution
• C) Infinite solutions
• D) More than one solution

Ans: B) No solution

11) Forces P and Q are acting along ceiling and floor of a rectangular room. What is the nature of the forces?

• A) Like
• B) unlike
• C) collinear
• D) parallel

Ans: B) unlike

Group “B”

12) For any positive integer n, (a+x)ⁿ = C₀aⁿ
+ C₁a^n-1x + C₂a^n-2x²+……+c_nxⁿ.

a) How many terms are there in the expression?

b) Write binomial coefficient in the expansions?

c) Write the general term of the expansion.

d) Write the relations among C (n, r-1), C (n+1, r) and C
(n, r).

e) What is the value of C₀+C₁+C₂
+…+C_n?

Solution:

(a) There will be (n+1) numbers of terms in the
expansion of (a+x)ⁿ = C₀aⁿ + C₁a^n-1x
+ C₂a^n-2x²+……+c_nxⁿ.

(b) The binomial coefficient in the expansion of (a+x)ⁿ
= C₀aⁿ + C₁a^n-1x + C₂a^n-2x²+……+c_nxⁿ
are: C₀, C₁a^n-1, C₂a^n-2,……C_n

(c) The general terms of the expansion is ⁿC_ra^n-rx^r.

(d) The relations among C (n, r-1), C (n+1, r) and C
(n, r) is ⁿC­_r + ⁿC_r-1 = ⁿ⁺¹C_r.

(e) The value of C₀+C₁+C₂ +…+C_n
is 2ⁿ.

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