Eggs that you buy from the store will not stay fresh for long  without refrigeration. Eggs that come right from the chicken can  kept at room temperature for weeks. Store bo â¦ ught eggs should be  refrigerated within a few hours of buying them just to be safe.ven with its natural (but easily cracked) calcium-carbonate container, a hard-cooked egg is a perishabl â¦ e food, so it shouldn't be kept at room temperature for more than two hours.   If kept in an unbroken shell and in the refrigerator about a week.
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. Sensitivity also varies with frequency, as shown by equal-loudness contours.
Normal human hearing ranges from 20 hertz to 20,000 hertz. Low-frequency sounds, below 20 hertz, are referred to as âinfrasoundâ and travel farther than high-frequency sounds. Frequencies above the range of human hearing (20,000 hertz) are referred to as âultrasonic.â.lthough the upper end of human hearing is about 20,000 hertz, deer can hear frequencies to at least 30,000 hertz. But, these high-frequency sounds must be louder because high-frequency sounds donât travel as far as low-frequency sounds. Hearing and Vocal Communication.