<span>The heart contains four chambers: upper left atria, upper right atria, lower left ventricle and the lower right ventricle. Oftentimes, the right atria and right ventricle are together referred to as the "right heart" and the left atria and left ventricle are referred to as the "left heart", however there are still four separate chambers.</span>
I think the answer is non reactive. As the outer shells gets filled ,valency decreases, so reactivity also decreases.
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205 bones i believe is your answer
Answer:
because scientist think it will help let us students learn more about the living world
