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.
Karst landforms are a type of topography formed due to dissolution of soluble rocks like limestone, dolomite and gypsum.Poljes also called as karst fields or karst polje are large flat plains found in karst regions. The word Polje means ‘field’. They are flat floored depression within karst limestone.
EXAMIANS