Best to send all SAT Subject Test Scores or just the required?

Hi, I have taken 3 SAT Subject Tests while in High School: Chemistry and Math Level 2 just this past June and Biology M at the end of my Sophomore year. Although my Chemistry (750) and Math Level 2 (800) scores are amazing, my Biology M (710) score is sub-par. (After all, with the exception of a few AP exams, this was my first standardized test.)

My question is whether it would be a good idea to send the score or just leave it out. I have talked to some MIT admission officers, and they told me I should decide whether I feel sending the score would hurt me or not. I am still a little confused, and although I feel I want the officers to know that I have decided to test my skills in more than just Chemistry and Math, I am also afraid that the low 710 might deem me less attractive as an applicant. If it helps, I designated on my application that I am interested in the Mathematics Department. Thank you!