<span>Its important not to have fingerprints on the cuvette when using a spectrometer because by using a spectrometer one measures the amount the amount of light that the solution in the cuvette absorbs at a certain wavelength. This tells you how much of the solute is dissolved in the solution. So if you get fingerprints on the cuvette, this could interfere with the light absorption and cause your readings to be incorrect. </span>
An externality takes place when an action which is being conducted attending an individual interest, has an effect on other third parties (this effect can be either positive or negative).
Improving the appearance of the property is considered a good externality, as it supposes an upgrade for the area in which is embodied. An improved property enhances its market value but also the market values of the surrounding properties of the neighbours.
The two dominant approaches are:
<span> the biological model and the learning model. The biological model focused on the biological facros that determine the magnitude of the drug addiction.
</span>The learning model on the other hand, focused on the behavioral aspects that might caused someone to constantly used the drugs.
