Intracellular fluid and extracellular fluid constitute what percentage of total body weight,respectively?

The $.....$ is the blood bank of the body.

In connection with the circulatory system,where are valves present?

Consider the following four statements regarding the human circulatory system:
$(a)$ Arteries have thick walls and have a smaller lumen compared to veins.
$(b)$ Angina is a sudden chest pain.
$(c)$ In the $ABO$ blood grouping system,a person with $AB$ blood group can donate blood to anyone.
$(d)$ Calcium ions play an important role in blood clotting.
Which two of the above statements are correct?

$A$: In an open circulatory system,the volume of blood is high,but blood pressure is low and irregular.
$R$: In a closed circulatory system,the volume of blood is limited,and blood pressure is high and regular.

Assertion $A$: Anemia is sometimes observed in humans.
Reason $R$: There is a deficiency of iron and copper in the human body.
Which option is correct for Assertion $A$ and Reason $R$?