A patient suffering from severe chest pain is admitted to the ER. After a series of tests, it is found that blood is flowing back into the left atrium as it is pumped into the left ventricle. Which valve is responsible for preventing this from happening? a. the aortic valve
b. the mitral valve
c. the pulmonary valve
d. the tricuspid valve

the miral valve

Explanation:

the miral valve us between the left atrium and left ventricle

edge 2021 biology test

precisely the author keeps the interest of readers not describing clearly the   kind of relationship in giselle's family. by doing this, readers had to imagine and assume how it was.   instead, the author described better scenes with dark star and the influence of books about horses in giselle's life and actions.   also the fact that she broke her arm but not referring to it in detail leads the readers to imagine and guess what could have occurred.