The answer to your question is A carpel
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.
Answer:
This suggests that the moustache is a releaser for aggression.
Explanation:
<em>Fixed action patterns</em> are instinctive programmed responses in different species that are triggered by a specific external sensory stimulus. These stimuli are called sign stimuli or releaser. When the sign occurs, the animal starts a sequence of acts in response to the stimulus and continuous until the series of actions is completed.
The black feathers resembling a mustache in a <em>Northern flickers</em> male are an external sensory stimulus. This trait that can provoke another male to respond aggressively, as a f<em>ixed action pattern</em>.
This trait might be considered as an <em>unconditioned stimulus</em>, which <em>provokes an unlearned or reflex reaction</em>. These aggressive responses are triggered by reflex.
