Final answer:
The greatest decline in hearing is typically seen in individuals ages 80-90. Hearing range for humans typically falls between 20 Hz to 20,000 Hz, and both age and damage from noise exposure can decrease this range. Amplification is necessary for those with hearing loss, often requiring significant intensification of sounds to be perceived as normal.
Step-by-step explanation:
The decline in hearing is known to occur with age. While hearing loss can begin earlier, it is typically more pronounced as people grow older. The options provided suggest various age ranges, but based on knowledge of human physiology and widely accepted research, the greatest decline in hearing is often seen in individuals ages 80-90 (c). However, it is important to note that this decline can vary from person to person, with some individuals experiencing significant hearing loss earlier or later than this age range.
With regard to the provided information relevant to hearing and perception, humans are capable of distinguishing two separate sounds if the frequencies vary by a minimum amount which is generally accepted to be around 1-5 Hz for low frequencies but can be much more at higher frequencies. The range of frequencies that humans can hear typically falls between 20 Hz to 20,000 Hz, which covers the spectrum from very low to very high pitches. This range can diminish with age or due to exposure to loud noises causing noise-related damage. For example, a child with a 60 dB hearing loss at 5000 Hz would require that tone to be significantly more intense to be audible compared to a 400 Hz tone. Similarly, a person with a hearing threshold 10 dB above normal at 100 Hz and 50 dB above normal at 4000 Hz would require a 100-Hz tone to be less intense than a 4000-Hz tone to be barely audible to them. As for individuals with a uniform 50-dB hearing loss at all frequencies, sounds need to be amplified by 100,000 times (or 5 factors of 10), to appear normal, though care must be taken not to over-amplify and potentially cause further damage.