Sound waves are produced by air flow coming from our lungs passing through our throat, more specifically our larynx and moving with two folds of tissue called vocal chords. The sound is made by the vibration of vocal chords, so the more stretched the chords are over the larynx, their frequency of vibration is higher, therefore producing higher-pitched sounds.
Answer: Yes, they have.
Explanation: The frequency, severity, and length of heat waves are increasing. Heat and humidity already kill an average of 1,300 people in the U.S. each year. Deadly heat waves of at least 20 days affect 30% of the earth's population. That will increase to 75% by 2100 if global warming isn't stopped.
okie dokie I'll check it out right away
