2. Importance of root and tuber crops in Africa. In Africa, roots and tubers are generally grown in countries located in the Sub-Saharan zones, notably in Nigeria, Ghana, Cote cÃ´te'D, Ivoire, Nigeria, Benin, Cameroon Central African, Republic.D.R, C, Tanzania, Mozambique, Angola, Uganda, Malawi madagascar And. rwanda
The healthy human ear can hear frequencies ranging from 20Hz to 20,000 Hz. Over time, the hair cellâs hair-like stereocilia may get damaged or broken. If enough of them are damaged, hearing loss results. The high frequency area of the cochlea is often damaged by loud sound.
Intensity, or loudness, is measured in decibels (dB). A person with hearing within the normal range with respect to loudness of sound can hear sounds ranging from 0 to 140 dB. A whisper is around 30 dB. Conversations are usually 50 to 60 dB. Sounds that are louder than 90 dB can be uncomfortable to hear.