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 hear sounds approximately within the frequencies of 20 Hz and 20,000 Hz. Anything below 20 Hz, typically cannot be heard although it can be felt. This can be experienced to when you feel the bass of a song. Likewise humans normally cannot hear any sounds above the frequency of 20,000 Hz.