Counter current involves blood in the capillaries flowing in the opposite direction to the flow of water flowing over them. Gases diffuse faster from one area to another when the concentration difference between the two areas is at its greatest, as compared to when the concentration difference is low.
Answer: water, wind, volcanic rock, sand, and other stuff that can pile up basically.
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.
