Textbook
Chapter 1: Biodiversity
Chapter 2: Ecosystem
Chapter 3: Nutrition
Chapter 4: Human health
Chapter 5: Water and Solution
Chapter 6: Acid and Alkalis
Chapter 7: Electricity and Magnetism
Chapter 8: Force and Motion
Chapter 9: Heat
Chapter 10: Sound Waves
Chapter 11: Stars and Galaxies in the Universe
Chapter 12: Solar System
Chapter 13: Meteoroid, Asteroid, Comet
Chapter 10: Sound Waves
Phenomena and Application of Reflection of Sound Waves
Characteristics of Sound Waves
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