Increasing the temperature will cause an increase in the kinetic energy of molecules which will change its state to gas.
If oxygen is not present, glycolysis would be followed by fermentation
Water gains energy during evaporation and releases it during condensation.
The answer is <span>Take consistent amounts of saliva samples from a number of people who have not eaten in 8 hours and measure the quantity of amylase in each sample.
First, the researcher needs to know the quantity of amylase in the <u>same</u> amount of saliva. Thus the amount must be consistent and not varying.
Next, people must not eat in 8 hours, so they are all in the same condition at the moment of collecting saliva. If some eat immediately before the sample collecting while some eat 8 hours before, the content of their saliva will be different.
For the correct results, all conditions must be the same.</span>