True: Dolphins use sound by echolocation, Sound is used by artists in concerts, Builders use sound to identify cracks in metal tubes, Children use sound to talk with each other, Police officers use sound to talk with each other , Ultrasound is used in hospitals to check the condition of babies in the wombs of pregnant women, You use sound for communication when you answer the question of your teacher , False: Doctors use sound to produce heat, People use ultrasound to sing in a concert, Dogs find their food using ultrasound,

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