Answer:
a) Growth of walking sticks.
Step-by-step explanation:
An independent variable is a characteristic that the researcher can change. In this experiment, the independent variable would be temperature.
A dependent variable, on the other hand, is the variable that you cannot change, but instead, it changes or depends on the independent variable. In this case, the dependent variable would be the growth of the walking sticks.
Why? Because the growth of these insects will depend on the temperature of each incubator.
All of the other options can be changed by the researcher, but what will happen -the result- when you change them will be the growth of the animals.