I believe the answer to this is Genetic Diversity.
Okay so Nancy wrote hers in expanded form is a method of representing a number through an addition statement by totaling the values of its digits.
Answer:
the first choice
Explanation:
The reason why it is the first choice is because you would need to experiment twice before concluding your experiment one has to be normal height and the second test has to be higher also the mass on the car also is a factor to the experiment.