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.
Forested wetlands are called as swamps. They are located all around the world. Freshwater swamps form along large lakes and rivers. Saltwater swamps are found along tropical and sub tropical coastlines.
EXAMIANS