In a parallel circuit, the current stays the same if you add a branch with the same resistance. So since an electrical current is a flow of charges, where are the extra charge particles coming from? Is there a limit to the number of charges in a circuit? Thanks

The answer is water molecules are split.cellular respiration and photosynthesis are complement  reactions to each other. these are reverse reactions. in cellular respiration glucose and oxygen yield water and carbon dioxide. so, when respiration begins,  glucose molecules are split. in the opposite reaction - in photosynthesis, carbon dioxide and water yield glucose and oxygen. thus,  when respiration begins, water molecules are split.

That big glowy thing in the sky is called the sun