A) A flap in the heart located between each atrium and ventricle.
Hope it helps! :)
Answer:
Negative feedback.
Explanation:
The production of erythropoietin by the liver and kidneys is a negative feedback because with the production of erythropoietin, our body tends to move to become more stable state. The erythropoietin is produced by the liver and kidneys to increase the production of red blood cells if the quantity of red blood cells are lower than the normal range. If the number of red blood cells are decreases the oxygen level in our body is low that leads to unstable condition of the body but when the concentration of red blood cells increases, the body move towards stability.
The correct answer is "reefs".
Shallow-marine environments are considered to be an area among the shore and deeper water, along with a reef wall or a shelf break. This surroundings is characterized by means of oceanic, geological and organic conditions, as described underneath.
