I think it is Free Radical.
Answer:Genetic testing involves examining your DNA, the chemical database that carries instructions for your body's functions. Genetic testing can reveal changes (mutations) in your genes that may cause illness or disease.
Although genetic testing can provide important information for diagnosing, treating and preventing illness, there are limitations. For example, if you're a healthy person, a positive result from genetic testing doesn't always mean you will develop a disease. On the other hand, in some situations, a negative result doesn't guarantee that you won't have a certain disorder.
Explanation:
Sequence of nucleotides that compose units of DNA.
the answer is external auditory meatus
Natural selection. This is what Darwin said would help organism adapt and survive.