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.
Humans can generally sense sounds at frequencies between 20 and 20,000 cycles per second, or hertz (Hz)âalthough this range shrinks as a person ages. Prolonged exposure to loud noises within the audible range have long been known to cause hearing loss over time.