The human heart beats about 100,000 times a day. At this rate it still takes it thirty yearsto beat one billion times .... Blood begins its journey in the arteries as pure oxygenated blood and flows to different parts of the body. It returns to the veins that carry impure blood from different parts of the body. The impure venous blood flows from the right side of the heart to the lungs for purification. Who did manufacture that perfect design, coincidence or blind nature!!!? In the lungs, when we inhale oxygen, the latter comes in contact with the impure blood and a sort of combustion takes place with the blood being purified. The blood gives out carbonic acid generated from the poisonous matter and takes in oxygen. The purified blood is taken by the four pulmonary veins to the left ventricle. The blood is later pumped from the left ventricle into the aorta, from the aorta; it passes to the different arteries of the body. The pure blood from the arteries goes to the capillaries. From the capillaries, it goes to the tissues. The tissues take in the oxygen and give out carbon dioxide. The veins carry the impurities to the right side of the heart. We have to ask some primitive questions to atheists and disbelievers and they have to answer it by little common sense: Length of circulatory system of human ranges from 50,000 to 60000 miles in a child's body and close to 100,000 miles in an adult. Scientists say that the circumference of the earth at the equator is 25,000 miles, if the blood vessels of an adult were lined up end to end, they would circle the equator four times! Who manufactured that precise design? The human heart beats about 100,000 times a day. At this rate it still takes it thirty years to beat one billion times. Can any disbeliever or atheist tell us about any human made any machine that works for 30 years without stop or any type of maintenance? (At end there must be a creator for any thing). The blood needs 20 seconds to circulate in the whole circulatory system. Who created that system, coincidence or nature? Any reasonable man should reach one result that there is only one great creator who created all of that. Allah says: ((such is) the artistry of God, who disposes of all things in perfect order: for he is well acquainted with all that ye do.) (Sûrat Al-Naml-verse88).