
Scientists studied ear muscles in people. Scientists played sounds. People listened. They used their ear muscles when they were trying to hear.
Photo Credit: ia_64/Getty Images
Heavy rain can make the puddles too big. The extra … read more
Morse code can be communicated with a flashlight. The flashes … read more
Many Asian Americans started communities. The picture shows people in … read more
© 2025 McGraw-Hill Education. All Rights Reserved.