Madison is trying to determine which science investigation she should do for the school science fair. She knows that some investigations involve an experiment and that some only involve making observations. Which question is one that she can answer by performing a scientific experiment, instead of only making observations?


Which extraction method yields the most DNA from fruit?


How did Watson and Crick determine the structure of DNA?


Which family members exhibit blue, green, and brown eyes?


Which organisms exhibit the most similar physical characteristics?