What condition occurs when fluid accumulates in the lungs, preventing them from breathing adequately?

Answer: Pulmonary edema

Explanation:

Pulmonary edema is the condition in which there is an excess of fluid in the lungs. This fluid gets collected in the air sacs which causes hindrance in breathing.

Most of the heart related diseases causes pulmonary edema. Pulmonary edema can be caused due to pneumonia, trauma in the chest wall and exercising at higher elevations. It is very fatal if not cured on time.

Hence, the correct answer is pulmonary edema.