The swelling and pain associated with inflammation are caused by the
a. destruction of bacteria by white blood cells.
b. expansion of local blood vessels.
c. secretion of antibodies.
d. secretion of antigens.

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.  

Death by starvation.

Pe.dometer would be the most useful to you for monitoring heart rate.