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CLASS 7 SUB-SCIENCE HALF YEARLY EXAMINATION MAX MARKS-40 TIME ALLOTED GENERAL INSTRUCTIONS 1. The question paper comprises four sections-A, B, C and D. There are 19 questions in the question paper. All the questions are compulsory. 2. Section A consists of question number 1 to 8. These questions are very short answer questions, MCQ’s and Assertion-Reason questions which should be answered in one word or on sentence. They carry one mark each. 3. Section B consists of question number 9 to 13. These are short answers questions which carry two marks each. 4. Section C consists of question numbers 14 to 18. These are also short answer questions which carry three marks each. 5. Section D consists of question number 19. This is long answer question and carries 5 marks. 6. There is no overall choice in the question paper however internal choices have been provided in some question. SECTION -A 1. Big cats have sharp teeth. Why? 2. When a flower is said to be bisexual. 3. Why soft drink bottles often crack when left in the freezer compartment for a long time? 4. Name the soil that has the right water holding capacity and has sufficient air. 5. Write the chemical symbol for Iron and Chlorine. 6. ASSERTION-When electricity is passed through water the products formed are Hydrogen and Oxygen gas.  Reason-Reaction in which more than one product is obtained from a single reaction is called displacement reaction.  Both assertion and reason are true and the reason is the correct explanation of the assertion.  Both assertion and reason are true but the reason is not the correct explanation of the assertion.  Assertion is true statement but reason is false.  Both assertion and reason are false.

7. ASSERTION-An increase in the temperature on the surface of earth leads to a phenomenon called ‘greenhouse effect’ which causes global warming. Reason-Carbon dioxide gas helps in trapping a part of the energy of sun rays in the earth’s atmosphere by not allowing that energy to escape.  Both assertion and reason are true and the reason is the correct explanation of the assertion.  Both assertion and reason are true but the reason is not the correct explanation of the assertion.  Assertion is true statement but reason is false.  Both assertion and reason are false. 8. Read the following and answer the given questions. Agriculture and deforestation, along with housing, industrial development and highway construction, destroy the protective canopy of vegetarian and greatly speed up erosion of soil. Overgrazing can change the grassland into deserts. The removal of topsoil by agents such as wind and water cause soil erosion. 1x3 (i) Agents of soil erosion are- a) Wind b) Water c) Plants d) Both a and b (ii) Factors given below speed up soil erosion – a) Agriculture b) Deforestation c) Industrial development d) All the above (iii) Grassland change into desert due to- a) Overgrazing b) Wind c) Plants d) Bacteria SECTION-B 1x2 9.In what ways vegetative propagation is better than sexual reproduction. 1x2 10.Write two difference between acids and base. Or Classify the following reactions into different types a) CaO+SiO2CaSiO3 b) KOH + Hcl Kcl+H2O c) Cu + 2AgNO3Cu(NO3)2+2Ag d) BaCO3BaO+ CO2

11.State the function of sucker pads on the feet of the red eyes frog. OR Mention two adaptive feature of a penguin that help it in swimming. 1x2 12. Give difference between infiltration rate and percolation rate. 1x2 13. In what ways does a clinical thermometer differs from an ordinary thermometer. 1x2 Or Why ice boxes are often made up of double walled containers? SECTION-C 14. Mention any 3 adaptations that have helped the polar bear to survive in the polar region. 1X3 15. Complete the below statements- (i) Cud chewing herbivore animals are called_________. They have special __________ chambered stomach. These animals first swallow the food quickly and store in their _________is an example of these cud chewing animals. 1X2 (ii) What is the role of bile juice in the process of digestion. 1X1 16. Write any 3 causes of soil pollution. 1X3 Or Give reason. (i)Earthworm is known as nature’s ploughman. 1X2 (ii) Humus is important component of soil. 1X1 17. Explain ingestion of food in amoeba by diagram 1X3 Or Explain how wind are caused 18. Differentiate between acidic, basic and neutral salts. 1X3 Or Write characteristics of soil profile in the given layers . (i)O Horizon (ii) A Horizon

(iii) R Horizon 1x3 1x2 SECTION-D 1x2 19. (i) neat well labelled diagram of parts of a flower. 1x2 (ii)What are disadvantage of vegetative propagation. Or ½*2=1 (i)Give reason for the following a) We prefer light colored clothes in summers b) Bottom of cooking utensils are often kept black. (ii) Write the chemical formula for- a) Aluminum oxide b) Copper sulphate (iv) Correct the following incorrect statement a) The largest gland in human body is salivary gland. b) Amoeba uses cilia for locomotion.