関連ワード:  class 7 science chapter 7 summary    class 7 science chapter 1 summary    class 7 science chapter 2 summary    class 7 science chapter 4 summary    class 7 science chapter 5 summary    class 9 science chapter 7 summary    class 7 science chapter 6 summary    class 10 science chapter 7 summary    class 7 science chapter 1 summary in hindi    class 8 science chapter 7 summary