Origins of the Domino Theory. In September 1945, the Vietnamese nationalist leader Ho Chi Minh proclaimed Vietnamâs independence from France, beginning a war that pitted Hoâs communist-led Viet Minh regime in Hanoi (North Vietnam) against a French-backed regime in Saigon (South Vietnam).
The human range is commonly given as 20 to 20,000 Hz, though there is considerable variation between individuals, especially at high frequencies, and a gradual loss of sensitivity to higher frequencies with age is considered normal.
The highest frequency that most humans can hear is 20,000 cycles per second or 20,000 Hz. This limit gets lower as humans age. Older people generally donât have as large of a hearing range as younger people. The lowest frequency a human can hear is only 20 Hz, but we can feel sounds lower than that such as for an earthquake. Humans can hear from about 20 - 20,000 Hz, under normal conditions.