What do chicken pox, measles, polio and influenza all have in common?

A- all caused by bacteria

B- all caused by viruses

C- all can be treated with antibiotics

D- all are incurable by the human body

stress fractures occur largely in the feet and legs and are common in sports that require repetitive impact, primarily running/jumping sports such as gymnastics or track and field.

blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. as the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs where it is oxygenated.