Science Class 8 Question Answer & Topics Video CROP PRODUCTION AND MANAGEMENTMICROORGANISMS: FRIEND AND FOESYNTHETIC FIBRES AND PLASTICSMATERIALS: METALS AND NON-METALSCOAL AND PETROLEUMCOMBUSTION AND FLAMECONSERVATION OF PLANTS AND ANIMALSCELL STRUCTURE AND FUNCTIONSREPRODUCTION IN ANIMALSFORCE AND PRESSUREFRICTIONSOUNDCHEMICAL EFFECTS OF ELECTRIC CURRENT