Determine whether the following is most likely to be controlled by a positive/negative feedback mechanism?

Determine whether the following is most likely to be controlled by a positive/negative feedback mechanism?

(A) The level of carbon dioxide (CO2) in the blood

User Comments

1. B is a positive (+) feedback response
2. B is positive, all the rest are negative.
3. (B) Blood clotting (+)
   
4. (C) the level of lutenizing hormone in females
   
5. (D) the level of thyroid hormone found in the blood