CBSE Class 7 Marking Scheme 2022 Science Term 2 Set 1

MARKING SCHEME TERM II SAMPLE PAPER - 1 MARKING SCHEME SUBJECT – SCIENCE CLASS - VII Qno. Answers Marks MCQs SECTION A 1 (d) All of these 1 2 (b) Lactic acid 1 3 (a) Arteries except pulmonary artery 1 4 (d) Fruit 1 5 (a) 2.1s 1 6 (b) Element 1 7 (a) Virtual and erect 1 8 (a) 2003 1 9 (a) Canopy 1 10 © Anaerobic bacteria 1 SECTION B 11 Clayey soil – 1 Proportion of fine particles is large. 1+1=2 2 Has good water holding capacity. Sandy soil - 1 Proportion of big particles is large. 2 Has poor water holding capacity 12 Exercise needs extra energy for which food breaks down very 2 rapidly by faster breathing. This makes us feel hungry. 13 NCERT text book, page no 127 1 +1=2 Diagram , Labelling (any 2 parts) 14 Speed of a bicycle = 2m/s Total time taken = 15 min = 900 s 1/2 Distance = speed x time ½ 2 x 900 = 1800 m 1 =2 15 Fertilisation – Fusion of male and female gamete 1+1=2 Pollination - The transfer of pollen grain from anther to stigma 16 (a) Heating effect of electric current 1+1=2 (b) Fuse or MCB 17 7 colours , VIBGYOR – 1+1=2 violet,indigo,blue,green,yellow,orange,red 18 By the process of photosynthesis and respiration,use and 1+1=2 consumption of oxygen and carbon dioxide goes on.Thus they maintain the balance of oxygen and carbon dioxide in the atmosphere. 80

19 Reasons – Population growth, Pollution, Industrial development, 1/2x4=2 mismanagement of water (or any other) 0R OR (a) Wastewater Treatment Plant 1 (b) 1 Aeration 2 Filtration 3 Chlorination 1 SECTION C 20 (a) NCERT text book, page no. 112, fig.10.4- Diagram + 1+2 labelling (b) Any one difference 1=4 21 (a) Correct definition 1+ (b) 1 Surroundings should be clean. 2 Sewage system in the home should be properly managed. 3=4 3 Some leakage or other problem in the sewage system should be reported to the municipality. ( or any other) 22 (a) Correct diagram 1 (b) Any one difference 1 (c) When the light passes through a convex lens, it concentrates at a point, so it can damage our eyes 1 permanently. (d) Concave lens. 1=4 OR (a) Real image – 1 Can be obtained on a screen. 2 It is always inverted. ½+ Virtual image- 1 Cannot be obtained on a screen. ½ 2 It is always erect. (b) Used in head lights of the cars, buses, shaving mirrors,used by dentists and doctors. ½+1/2 (c) Real and inverted image is formed but if the object is placed very near to the mirror, then the image formed is virtual and erect. 1 (d) Convex mirror 1=4 81