Which of the following determines blood volume?

the strength of heart contraction
the amount of water in the blood
abo blood type and rh factor
heart rate and respiratory rate

Option B, The amount of water in the blood

Explanation:

This can be understood from the scenario as described below –

Suppose the quantity of water (volume by volume, v/v or %) in blood is equal to X litre which constitute Y% of the total blood volume.  

Then, the volume of blood can be determined in the following ways-  

Y % of blood volume is equal to X liters

Then  

litres

Blood Volume litres

Thus, in this way if amount of water in blood is known, then the blood volume can be determined.

geologic time scale (for gradpoint) =)