West Bengal Board Model Questions & Answers : Class-12 Life Science
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West Bengal Board Model Questions & Answers : Class-12
Exam Name : West Bengal Board Model Questions & Answers
Subject : Life Science (Sample Paper's I,II & III )
Class : 12th
Model Question Biology − 3
Sankari Prasad Bhattacharyay
Ballygunj Govt. High School
Group − ‘A’
Q1. Answer the following questions : (Alternatives are to be noted) 2 x 7 = 14
(a) State two differences between tracheid & trachea.
Ans.
Tracheid Trachea
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1. |
Structure |
1. |
Presence of all types of |
1. |
Presence of all types of |
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thickening except |
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thickening including |
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bordered pits. |
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bordered pits. |
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2. |
Function |
2. |
Major conducting xylem |
2. |
Major conducting xylem |
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element of non−flowering
plants. |
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elements of flowering plants. |
(b) State two differences between the vascular bundle of Root and Stem.
Ans.
Vascular bundle of stem Vascular bundle of root
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1. |
Number |
1. |
Many vesicular bundle
arranged in a ring in dicot |
1. |
Number of vascular bundles
and less i.e. 2 − 5 in number |
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stem. |
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in Dicot root. |
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Numbers vascular |
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The vascular bundles are 6 − |
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bundles are scattered in
the ground tissue in |
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8 in number in monocot root. |
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monocot stem. |
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2. |
Types |
2. |
Conjoint, collateral or |
2. |
Radial, closed |
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bicollateral |
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(c) State two differences between Penaeid & Non penaeid Prawn.
Ans. Peneid Non−peneid
Habitat 1. Saline Water prawn 1. Fresh water prawn
Structure 2. The first three thoracic legs are chelate
Ex − Penacus indicus Ex − Macrobrachium rosen burgii
OR Write the scientific names of two Pearl oysters.
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Ans : |
1. |
Pinctada fucata |
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2. |
Pinctada atropurpurea |
(d) Write one symptom each of Flacherie & Muscardine of silkworm.
Ans : 1. Flacherie : (i) The body of the larva becomes soft and black.
2. Muscardiine : (i) The body of the larva becomes stiff and is covered with powdery white material.
(e) State the name of four abnormal composition of urine.
Ans : (i) Blood, (ii) Pus Cells, (iii) Protein (albumin) (iv) Ketone bodies.
OR State the role of skin in excretion.
Ans : (i) The skin excretes water, salts, uric acid etc. through sweat and irreversible respiration.
(ii) The skin excretes waxes, hydrocarbons, cholesterol etc. through sebum. Hence the skin is called accessory excretory organ.
(f) Write the now of four hormones secreted from placenta.
Ans : (1) Human chronic gonadotrophin (HCG) (2) Estrogen (3) Progesterone
(4) Placental prolactic.
OR State the one function each of somatostation & Prostaglandin.
Ans : (1) Somatostaion − It inhibits the secretion of insulin and glucagon from the pancreatic islets.
(2) Prostaglandins − Inhibit gastric acid secretion and formation of peptic ulcer.
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Click Here to Download Sample Paper I
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Click Here to Download Sample Paper II
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Click Here to Download Sample Paper III
Courtesy: West Bengal Board