I believe the answer is b hope this helps
Answer:
I think it is colon because the other ones did not make sense
Hope you have a good day
In a centrifuged sample of blood the PLATELETS should not be in the plasma portion of the sample. Centrifugation of blood samples separates the blood to its constituents on the basis of their densities. Platelets will be found on the middle region of the separation and not in the upper region where plasma is .
An increase in A produces and increase in X
This is a positive feed back mechanism. This mechanism enhance or amplify changes. This tends to alter the balance away from equilibrium because one hormone will increase the release of the other hormone. An example of this is the child birth. During labor, oxytocin is released to increase the uterine contraction the release of oxytoocin will be induced by the contractions of uterus. This will go on until the child was born. Just remember positive feedback enhance the original stimulus.
