The mineral element found in the blood of vertebrates is . . . . . . .

The chief difference between $RBCs$ of human and frog is:

The number of $WBC$ per $mm^3$ of human blood is approximately:

If the mother has blood group $A$ and the father has blood group $AB$,which of the following blood groups cannot be present in their child?

$A$ person with blood group $AB$ is considered a universal recipient because they have:

You are required to draw blood from a patient and to keep it in a test tube for the analysis of blood corpuscles and plasma. You are provided with the following four types of test tubes. Which of them will you $NOT$ use for this purpose?