Answer:
Wing length
Step-by-step explanation:
According to the given excerpt, independent variable is 'wing length' and dependent variable is 'amount of time it takes for helicopter to hit the floor'.
Independent variable refers to the variable that do not undergo any change or shift in the course of the experiment of research. The other variables are measured using the constant independent variable. The value obtained from the independent variable is independent. On the other and, the dependent variable witnesses change with respect to the independent variable.