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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The third example will be “cancer”
Endocrine Signaling
Signals from distant cells are called endocrine signals; they originate from endocrine cells. In the body, many endocrine cells are located in endocrine glands, such as the thyroid gland, the hypothalamus, and the pituitary gland.
Answer:
nucleus
Explanation:
eukaryotic has a nucleus, prokaryotic does not
