The weather fronts are responsible for the movement of weather across the united states and canada
The diaphragm is the large dome-shaped muscle that rests right under the lungs and separates the abdominal cavity from the thoracic cavity. The contractions of the diaphragm are what truly facilitate the movement of air in and out of the lungs. The contraction of the diaphragm, or breathing in, leaves more room in the chest cavity for the lungs to expand as the diaphragm "tightens". The expanded lungs are filled with oxygen-rich air which is then is diffused through capillaries to different parts of the body. The process of breathing out occurs when the diaphragm relaxes, slowly resuming its position its original position in the chest cavity. When relaxing, carbon dioxide is forced out of the lungs.
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Answer:
The correct answer is 4.ecosystem.
Explanation:
An ecosystem is a system, that is, a set of elements that interact with each other, in which such elements are: physical environment, living beings and their interactions (predator-prey, parasite-host, competition, symbiosis, pollination, distribution of seeds , etc.) The interrelation between living beings (competition, parasitism, etc.) occurs through cycles of matter and energy flows on which the functioning of the entire ecosystem depends.
