The answer is, all three carbons from glucose molecules enters the Kreb cycle. But three at a time only. One molecule is broken down to two pyruvate molecules and then used in Krebs cycle. Which means that one glucose molecules leads to two cycles of the Kreb cycle with three carbons going to the cycle at one time.
Cellular respiration is the metabolic process by which a cell produces usable energy in the form of ATP. In order to accomplish this cells require Glucose and Oxygen to form the reaction which produces ATP and the byproducts of Water and CO2.
In reality its a complex topic however this is the basic form.
When a muscle receives nerve signal contracts and pulls on a tendon.
When the surface water is heated by the sun it dissolves more salt i believe
