Failure in a particular structure of the heart tends to cause a backup of blood in the lungs. What is this particular structure?

The correct answer is left ventricle.

Explanation:

The heart of a human being is differentiated into four chambers, that is, two ventricles and two auricles. Heart functions as a pumping organ and mediates both deoxygenated and oxygenated blood in the left and right ventricles. If any of the chambers is not working effectively, it may result in a specific disease in the individuals.

In case, if failure of the function of the left ventricle of the heart takes place then a disease termed as pulmonary heart failure results. The function of the left ventricle is to carry blood away from the heart to the tissues of the body, thus, its failure may result in the backup of blood in the lungs.