Serum differs from blood in

The ratio of $RBC$ to $WBC$ in man is (in $: 1$)

If the foetus is $Rh^+$ and the mother is $Rh^-$,then:

Choose the correct statements regarding human blood:
$I$. The volume of blood in an adult is $5 \; L$.
$II$. It constitutes $30-35 \; \%$ of the total extracellular fluid.
$III$. Glucose concentration in the blood is $50 \; mg / 100 \; mL$.
$IV$. Cholesterol concentration in the blood is less than $200 \; mg / 100 \; mL$.
$V$. Urea level in the blood is $10 \; mg / 100 \; mL$.
The option with correct statements is:

Which of the following is essential for the process of blood clotting?

Which of the following has the least consistency in shape?