you don need to actually chew the bread. you can just break it up into smaller pieces. which variable will you change in your investigation?

The type of bread (independent variable)

Explanation:

You can just change the type of bread you are eating and just hold it in your mouth to test your hypothesis of not having to chew the bread. It’s the easier thing to change when making the experiment. Now your bread is your independent variable because you are not changing anything else but the type of bread. Not sure if your question is talking about the technical terms for the variable or what actual variable in the experiment, so I put down both.

"1. it should be, it has been for about 20 years, and it's really not much different in the end than breeding animals to have particular traits. there are always concerns about genetically engineered animals/plants affecting the environment in unexpected negative ways, but i can't think of an example where the fears didn't turn out to be baseless.  

first, as you point out, it would be a great advance in pharmacology, to be able to tailor drugs and their doses to me. the pros involve better medical treatment. the cons involve privacy issues like insurance companies denying coverage to people with genetic risk factors. looking at dna markers wouldn't affect the frequency of genetic diseases, but it would allow detection of them earlier. and ok, actually i suppose that if people used this information to avoid having children with genetic diseases, some might decrease in frequency."