Three variables might be food availability (biotic), humidity conditions (abiotic) and temperature (abiotic), and it can be confirmed by measuring conditions (independent variables) in nature.
An independent variable is any variable that is not changed by other variables in an experiment.
In this case, the temperature represents an independent variable to be used during the experimental procedure, whereas beetle growth might be the dependent variable.
A plausible explanation or hypothesis might be that the temperature under logs is suitable to sustain the growth of beetles.
In conclusion, three variables might be food availability, humidity conditions and temperature, and it can be confirmed by measuring conditions (independent variables) in nature.
Learn more about the independent variable here:
https://brainly.com/question/82796
#SPJ1