In a controlled experiment, which variable does the investigator change?

Which of these describe conduction transfer of heat between two objects that are touching transfer of heat by the actual movement of war matter the process in which energy is imitated by one of the object transmitted through space and absorbed by another a process in which energy is released by the molecules breaking apart

Waves that cause the most damage during an earthquake are a. surface waves c. s waves b. p waves d. ocean waves

How would a small bar magnet be oriented when placed at position x?