Consider a test tube of blood that has been centrifuged. in what layer (top, middle or bottom) are the following substances located? i. most of the oxygen ii. most of the carbon dioxide iii. red blood cells iv. white blood cells v. platelets vi. albumin vii. antibodies (immunoglobulins) viii. blood clotting proteins ix. hemoglobin x. dna xi. glucose

Layer:

*- top - Most of the carbon dioxide / Albumin / Antibodies  (immunoglobulins) / Glucose

*- middle - Platelets / White blood cells / Blood clotting proteins

*- bottom - Most of the oxygen / Red blood cells / Hemoglobin / DNA

Explanation:

When the blood is centrifugated, if this is not anti-coagulated, the blood is separated in layers:

*- on the top it is found the serum, compounded by water, proteins as albumin and antibodies and solutes as gases as carbon dioxide and some nutrients as glucose

*- in the middle it is found the blood cloth, compunded by Platelets and Blood clotting proteins, right under this, are trapped the White blood cells  

*- at the bottom, as the most heavy compounds, it is found the red blood cells with the most of the oxygen attached on the hemoglobin and the DNA

the element that provides strength to the exoskeletons of clams and oysters is phosphorus.

this is so because calcium carbonate is the main component in the shells. calcium carbonate is strengthened by phosphorus.

explanation: