The answer is letter B.
When an injury occurs to a particular part of the
body, the blood vessels automatically expand to allow the increase of blood flow
in the affected area. This causes swelling which is a result of white blood
cells that travel to the affected area which automatically causes it to heal.
White blood cells are an important component of blood that are responsible for the repair of damaged tissues. They are bigger in structure because of the role
that they play in tissue repair and immune system reactions.
