Well you can cancel a few out...
cook - no, I mean you're just cooking you may not know a lot about nutrition
epidemiologist - they determine diseases and such, so no.
Dietitian - Yes, expert in nutrition
Health Educator - I mean maybe, but they may not know anything about nutrition
Answer
one of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome.
Answer:
I believe the answer is Intensity
Explanation:
I got it just from putting each word into the blank and seeing which one made the most sense and this is what I found to be the case.