is this valid

Question

To determine if there is a link between microwaved food and cancer, your friend proposed an experiment. She suggested that for the next year she will eat exclusively microwaved food, while you can exclude microwaved food from your diet, you both were tested after a year if either of you developed cancer

list 4 problems with this

Is this experiment valid

Answer 1

No, it is not valid. Problems: 1. Microwaved food may contain more salt and fat, making the food, bit preparation, a link to cancer. 2. To be quantifiable, how does one "test" for cancer given the enormous numbers and types of cancers? 3. Cancers can develop years after exposure, making the testing invalid on an immediate cause and effect basis. 4. The two participants would have to eat the exact same foods, holding constant dietary variations as a variable.