Absolute zero is the coldest possible temperature, at which no heat is left in a substance and its particles display no motion whatsoever. Absolute zero is equal to 0 K on the Kelvin scale, which is... Absolute zero is the coldest possible temperature, at which no heat is left in a substance and its particles display no motion whatsoever.
Serum is plasma that has been allowed to clot. It is prepared in the same way as plasma; however, the blood is collected into a tube with no anticoagulant. While spinning in the centrifuge, the clot moves with the cells to the bottom of the blood collection tube, leaving the serum on top.
Serum chloride: Serum chloride concentrations change for only a few reasons - 1. Can dip if serum sodium dips also: will follow sodium. 2. Can dip if serum bicarbonate (sodium bicarbonate) rises: reciprocal change. 3. Chloride thus is a secondary anion -- it follows another ionic change as above.