While most would agree that our circulatory system is vital to life, many of us don't fully appreciate the almost miraculous workings of that system.
Your heart pumps about one-hundred thousand times every day. That means that your heart pumps the equivalent of 10 tons of blood every day or 80 million gallons in a lifetime. Your circulatory system brings that blood to every cell in your body through a capillary network that is so large that the combined capillaries of only four people, stretched end to end, would reach from the Earth to the moon!
But your circulatory system involves quality as well as quantity. The chemistry of your blood is monitored and adjusted to within incredibly fine limits to keep it in precise balance second by second, day by day, year in, year out. For example, the acidity of your blood is adjusted constantly to within one part in a hundred million.
Our circulation system cannot be simply "good enough"; it has to work perfectly. So if mindless evolution created us, it had to make the whole system perfect the first time. There is no room for millions of years or for a poorer circulation system to be improved by mutations. Here, the facts clearly support Scripture, strongly indicating that we were created in finished form – not developed slowly by trial and error.