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.
Dispersed Settlements − In these kind of settlements, houses are spaced far apart and often interspersed with fields. However, the market and some other activities in these settlements are centralized where they participate together.
EXAMIANS