Answer: Option D
Explanation:
The bacteria can undergo cell differentiation in response to the environmental conditions.
The oxidative stress, antibiotic exposure, stress conditions are some of the external conditions due to which the bacterial cell can respond in the cell differentiation.
The bacterial species can divide based in the conditions in which they are put. So it is true that under stress conditions the bacterial cell can undergo cell differentiation.
Ductus Arteriosus is a blood vessel normally present in fetuses during development. The blood vessel is designed to bypass the pulmonary artery and brings blood to the Descending Aorta, as the fetus cannot breath through the lung (being as they are fluid filled). This is normally not a problem because oxygenated blood comes from the mother's blood supply.
Patent Ductus Arteriosus, is what happens when that vessel does not close. While not as dangerous as other congenital defects. However, because there is still a bypass, blood that normally need to be oxygenated by going through the pulmonary arteries to the lungs, can be diverted and placed into the blood stream without vital oxygen. This condition may eventually lead to CHF (congestive Heart Failure) and Pulmonary Hypertension if not treated.