Our lives hang on a thread. A constant flow of rich blood must reach cells throughout the body, delivering oxygen and essential nutrients to our extremities, while removing waste products like carbon dioxide. Stop the flow for just a few minutes, and life will cease.
How did the Creator ensure a steady flow? He gave us a pump made of soft flesh, not of hard steel. Estimates vary, but this powerful muscle pushes blood through at least 1,500 miles (2500 km) of blood vessels, some as narrow as one red blood cell. The heart must keep beating 100,000 times a day without tiring or malfunctioning.
We are a walking miracle, exquisitely designed for life on Earth. Just consider three engineering challenges that our heart has to overcome.
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