NATIONAL EXAMINATIONS BOARD [NEB]
NEB - Grade XII
2079 (2022)
Biology
Regular Students | Subject Code: 2021'N'
Time - 3 hrs
Full Marks - 75
Pass Marks - 27
Please complete the first section I (Botany) and then section II (Zoology). The answer to each section should be separate in the same answer sheet.
Candidates are required to give their answers in their own words as far as practicable. The figures in the margin indicate full marks.
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Note: Don't use Dark mode
Section: I (Botany)
Group A
Rewrite the correct options for each question in your answer sheet. 5x1=5
1. In a monohybrid cross of two heterozygous parents (Rr), what would the expected genotypes of the offspring be?
A) 1Rr:2Rr:1rr
B) 1rr:3RR
C) 3Rr:1rr
D) All Rr
C) 3Rr:1rr
D) All Rr
2. Which of the following cells in an embryo sac degenerate after fertilization?
A) Synergids and primary endosperm cell
B) Synergids and antipodal cells
C) Antipodal cells and primary endosperm cell
D) Eggs and antipodal cells.
3. The diagram shows that Two Cells P and Q are in contact with one another but are separated by the semi-permeable membrane. The osmotic pressure of cell P is 15 atm. and that of Q 12 atm. The turgor pressure of cell P is 10 directions will the water be more?
A) From cell P to cell Q
B) From cell Q to cell P
C) There will no movement if water
D) Water can move either from cell P to Q or from cell Q to P
4. Which one of the following parenchyma cells makes the aquatic plants light and helos buoyant?
A) Prosenchyma
B) Assimilatory parenchyma
C) Aerenchyam
D) Stellate parenchyma
Cells P
| Op = 15 atm TP = 10 atm |
Cell Q
| Op = 12 atm TP = 10 atm |
5. In an economically important plant species, embryo mortality is very high. What method do you suggest to check the mortality?
A) Micropropagation
B) Polyploid mutaition
C) Embryo culture
D) Meristen culture
Group B
Give short answers to the following questions. 4x4=16
6. 'Meristem is also known as Juvenile tissue'. Justify, Explain the types of meristem on the basis of position. 1+3
7. What are the differences between transportation and guttation? 4
OR
Explain in brief the significance of polyploidy with examples.
8. Write the salient features of the direct embryo in reference to its development pattern with labeled diagrams. 2+2
9. 'Hybridisation is a modern breeding method for the development of crop plants with desired characters as well as hybrid vigor'. Justify this statement by describing various steps of the hybridization procedure in plants. 1+3
Group C
Give long answers to the following questions. 2x8=16
10. Mutation is important from the evolutionary point of view. Give reasons. How does gene mutation occur? Explain its types. 2+2+4
OR
Why is Drosophila melanogaster selected for genetical study? The inheritance of sex-linked traits follows the criss-cross pattern of inheritance'. Justify this statement by describing with special reference to the eye color of Drosophila. 3+5
11. The source of oxygen in photosynthesis is water but not carbon dioxide. Explain with reasons. Briefly describe the Hill reaction. 2+6
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Section: II (Zoology)
Group A
Rewrite the correct options for each question in your answer sheet. 6x1=5
12. Which of the following tissues possess fat globules?
A) Arcelor tissue
B) Adipose tissue
C) Blood plasma
D) Striped muscle
13. What are the Sequential steps involved in process of gametogenesis?
A) Multiplication, growth, maturation
B) Multiplication, maturation, growth
C) Growth, multiplication, maturation
D) Maturation, growth, multiplication
14. When organ transplantation occurs between two genetically identical individuals, what will be the type of transplantation among the following?
A) Auto graft
B) Allo graft
C) Hetero graft
D) Iso graft
15. Overpopulation causes adverse consequences in society. Highlight which of the following can control overpopulation?
A) Early marriage
B) Polygamy
C) Family planning
D) Food supply
16. In the middle ear of a human being there are three ear ossicles. identify and select which of the following ear ossicles are arranged in the correct sequence?
A) Malleus, Incus, Stapes
B) Malleus, Stapesm Incus
C) Cochlea, Incus, Malleus
D) Malleus, Incus, Saccule
17. Pancreas is a gland having exocrine and endocrine functions. Its exocrine part is the pancreatic acini. What would be the endocrine part?
A) Zono glomerulosa
B) Islet of Langerbans
C) Zono reticularis
D) Adenohypophysis
Group B
Short Answer Questions. 4x4=16
18. How would you elaborate on the different types of simple epithelial tissues in animals? Support with diagrams. 3+1
19. Describe the process of oogenesis in animals with a diagram. 3+1
Or
Define the term in-vitro fertilization. Describe its process.
20. Study the given diagram of V.S. of the human eye and answer the following questions. 2+2
a) Label A, B, C, and D
b) Write one function for each of the parts labeled.
21. Kidneys are the organs that filter the blood to remove the wastes and keep the electrolyte in balance. If the kidneys do not function normality, various renal disorders are observed. Highlight any two common renal disorders in human beings. 4
Group C
Long Answer Questions. 2x8=16
22. Explain cholera as an acute diarrheal disease. Discuss, its causative agent, mode of transmission, and symptoms. Mention its control measures. 1+1+2+2+2
23. Draw a labeled diagram of the alimentary canal of a human being. How would you explain the digestion of proteins in the gut? Justify the relationship between amylase and lipase enzymes in the digestion of food. 3+4+1
OR
Justify the statement "sino-auricular node is a natural pacemaker." What would you suggest if the natural pacemaker does not function normally? How do you test blood grouping in human beings? 3+2+3
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