Answer: A
Explanation: Its three leafs and tear drop shaped.
The body system that directly provides for this demand is the circulatory system. When you exercise, the circulatory and muscle system cooperate, in order to meet the increased needs for strength and energy. The circulatory system involves the network which delivers blood to every part of your body. This flowing of blood ensures that the tissues are oxygenated and rich in necessary nutrients. During exercise, more blood flows to and from your muscles, in order to deliver the necessary amounts of oxygen to complete the aerobic respiration.
Answer:
Watson and Crick were able to develop a more accurate molecular structure because they had access to x-ray crystallography! Pauling didn't actually failed, he just did't have the same means!
Explanation:
By the way, is now known that the real discovery of DNA molecule was made by Rosalind Franklin. Any doubts you can send me a message!
