Answer:
The question is unclear, however, it can still be answered based on understanding of the topic, with correct explanation.
The independent variable is the HELICOPTERS MADE FROM DIFFERENT MATERIALS
Step-by-step explanation:
The independent variable in an experiment is the variable that the experimenter manipulates or changes in order to effect a response in the dependent variable. The independent variable is also called the experimental variable.
In this case, Ben makes five paper helicopters using different materials and tests the amount of time each paper helicopter will take to fall. Hence, the PAPER HELICOPTERS MADE FROM DIFFERENT MATERIALS is the independent variable, which determines how long they will fly (dependent variable)