<span>Cross bridges are created when myosin heads bind to ATP. This phenomenon is basically muscle contraction at work. In order for myosin heads to be bound with ATP at the actin active site, it must be excited with Calcium.
Once myosin heads bind with ATP, it begins to slide and perform muscle contractions in the body, allowing a person to move.</span>
<span>A scientific theory is a well-substantiated explanation of some aspect of the natural world that is acquired through the scientific method and repeatedly tested and confirmed through observation and experimentation.</span>
Answer:
C. Oxygen & Hydrogen.
Explanation:
The body is made of 65% Oxygen, 18% Carbon, 10% Hydrogen, 3% Nitrogen, and 4% other elements.