NCERT CLASS 9 SCIENCE CHAPTER 12 – IMPROVEMENT IN FOOD RESOURCES QUESTIONS AND ANSWERS SECTION 1: IN-TEXT QUESTIONS AND ANSWERS Q1. What do we get from cereals, pulses, fruits and vegetables? Answer: Cereals: They provide carbohydrates, which are the main source of energy. Pulses: They provide proteins, which are required for growth and repair of the body. Fruits and Vegetables: They provide vitamins and minerals, which protect our body from diseases and maintain good health. Q2. How do biotic and abiotic factors affect crop production? Answer: Biotic factors: These include insects, pests, rodents, weeds, fungi and bacteria. They damage crops, cause diseases and reduce crop production. Abiotic factors: These include temperature, humidity, drought, salinity, waterlogging, floods and soil conditions. They affect the growth and development of crops and may reduce their productivity. Q3. What are the desirable agronomic characteristics for crop improvements? Answer: The desirable agr...

  NCERT CLASS 9 SCIENCE CHAPTER 8 – FORCE AND LAWS OF MOTION QUESTIONS AND ANSWERS SECTION 1: IN-TEXT QUESTIONS AND ANSWERS Q1. Which of the following has more inertia? (a) A rubber ball and a stone of the same size. (b) A bicycle and a train. (c) A five-rupee coin and a one-rupee coin. Answer: (a) A stone has more inertia because it generally has more mass than a rubber ball of the same size. (b) A train has more inertia because it has more mass than a bicycle. (c) A five-rupee coin generally has more mass than a one-rupee coin. Therefore, it has more inertia. Q2. In the following example, try to identify the number of times the velocity of the ball changes: "A football player kicks a football to another player of his team, who kicks the football towards the goal. The goalkeeper of the opposite team collects the football and kicks it towards another player of his team." Also identify the agent supplying the force in each case. Answer: The velocity of the football changes thr...