Compare and contrast the systems of flatworms to the systems of sponges and
cnidarians. Use the terms circulatory system, respiratory system, and excretory system
in your answer.

Which statement best describes how the loudness of the sound affects the high-pressure region created by the sound wave? a. a louder sound has no effect on the pressure created. b. a louder sound means a high-pressure region that is higher. c. a louder sound means a high-pressure region that is not as high.