Professor Zander wants to know how loud a certain noise must be in order to be heard from a distance of 50 feet. This question involves the concept of .

Explanation:

The smallest level of energy required by the external stimulus to be detectable by our senses is called absolute threshold. It is used in neuroscience, it helps us to find the minimum level of stimulus that a person's senses can detect.  

Examples: Vision:A candle flame kept 20 miles away

Hearing - A clock ticking 20 feet away.

Professor Zander is also using the concept of absolute threshold to find loudness of sound that would be detectable form 50 feet away.

yes

it is because 3 because the citizen the northern democratic party watned the warning on red to blue because it is purple. lol

answer; presidential election years;