According to Alfred Wegener, all the major continents formed one giant supercontinent, called Pangaea. About 200 million years ago, the supercontinent Pangaea began to rift.
Ultrasound refers to a sound wave with a frequency greater than the upper limit of human hearing, which is generally over 20 kHz. In general, humans can hear sounds with a frequency between 20 Hz and 20 kHz.
EXAMIANS