External stimulus. The rain is something out of your control while you're waiting. Rain is not something you are doing nor is it a response to you waiting for the bus.
<h2>Answer:</h2>
The correct answer is the option C.
Which is we add equal amount of salt in all the water samples.
<h3>Explanation:</h3>
- As in experiment we have to indicate that the boiling point of water increases with the addition of salt.
- Now we also know that water contains many salts as compared to the distilled water.
- So the boiling points of simple water and distilled water would be bit different.
- So we cannot choose one for our experiment. Instead we use all water samples of equal volume adding equal amount of salt in all samples.
- Then we will compare results for a net answer/result of experiment.
<span>The burners must be turned off because, in the case of liquid chromatography, the eluant solvents being used are flammable. Leaving the burners lit could cause the eluant to catch on fire, putting the scientist at risk.</span>
In most cases, one uses tests whose size is equal to the significance level.
i would say by collecting data
They both help the envirment