Answer:
The breating rate is the dependent variable because it can be affected by varying weights.
Explanation:
In an experiment, the dependent variable is the variable that is not manipulated but is influenced by the changes that are done to the independent variable. In other words, it depends on the independent variable.
So in this case, the breathing rate is the dependent variable and the weight differences is the independent variable because the change in weight is what is changed to see if it will affect the breathing rate, which is the dependent variable.