the place where the temperature is measured the thermometer used to take the measurement the person reading the temperature measurement the time of day when the temperature is measured
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Students want to test how the temperature changes each day throughout the year. Which of the following does not have to be kept the same during the test?
Possibilities:
- the place where the temperature is measured
- the thermometer used to take the measurement
- the person reading the temperature measurement
- the time of day when the temperature is measured

the person reading the temperature measurement