The respiratory system always needs iron. The red blood cells are in charge of the transport of O2. They need iron to do this.
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99% of calcium is found inside the cells of the body.
Answer:Use the word RNA (Ribonucleic acid) in a sentence
Explanation:Viruses represent a large group of infective agents that are composed of a core of nucleic acids, either RNA or DNA, surrounded by a layer of protein.
