Mechanical waves can move through which of the following? water air vacuum a and b

Aballet student who learns with the of his instructor is demonstrating learning.

Acompound machine is also called a machine. a. force b. simple c. complex d. directional

At very high pressures, gases become and will eventually a) more dense; become hotter b) more dense; change to a liquid or solid c) less dense; combust d) less dense; turn into a liquid