Ultrasonic have__________________?A. frequency in the audible rangeB. frequency is greater than 20 kHzC. frequency lower than 20 HzD. all of above 0 0 votesArticle Rating Subscribe LoginNotify of new follow-up commentsnew replies to my comments Label {} [+] Name* Email* Website Label {} [+] Name* Email* Website 0 Comments Oldest Newest Most Voted Inline FeedbacksView all comments
