<span>The lasers are red, meaning that they are giving off light in the longest wavelength part of the visible region of the electromagnetic spectrum</span>
As per the question the color of laser light is given as red.
If we arrange all the electromagnetic waves in the decreasing order of frequency ,then the electromagnetic spectrum contains gamma ray as the first which is followed by all other electromagnetic waves according to their frequency.
The visible light ranges from 400 nm to 700 nm which contains sunlight i.e white colors with it's constituent colors starting from violet to red. The red color is the longest wavelength part of the visible region.
The wavelength of visible light is longer than ultraviolet wave but smaller than infrared radiation. Except the bisible region,the color of radiation is invisible to eye.
As per the question the color of emiited laser radiation is red .Hence it must lie in the visible region of the electromagnetic spectrum.
I personally believe one key disadvantages is the cost of maintaining the equipment unlike the gym where you have to subscribe for the month or the year and forget about anything, owning the gym equipment comes with the extra cost and responsibilities of maintenance to the owners.
Technique of comparing abundance ratio between radioactive isotopes to a reference isotope to determine the age of a material called radioactive dating. It determines the age by having a more abundance of isotopes in the cellular being.
