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.
People lose the ability to hear sounds of high frequency as they get older. The highest frequency that a normal middle-aged adult can hear is only 12-14 kilohertz. Also, the hearing range for men worsens more quickly than the hearing range for women.