Which of the following is an anticoagulant and prevents blood clotting within the blood vessels?

$A$ person meets with an accident and a great loss of blood has occurred. There is no time to analyze his blood group. It is safe to transfuse blood of group:

Red bone marrow of the bone produces

The old and worn-out $RBCs$ are filtered out by:

Which of the following does not help in the process of blood clotting?

The figure shows a human blood cell. Identify it and give its characteristics.