I believe the correct answer is "Carbon dioxide"
A to move around is the answer
Answer: Capillaries connect the arterial system — which includes the blood vessels that carry blood away from your heart — to your venous system. Your venous system includes the blood vessels that carry blood back to your heart. The exchange of oxygen, nutrients, and waste between your blood and tissues also happens in your capillaries.
The protein structures can be classified into four levels, namely the primary structure, secondary structure, tertiary structure, and quaternary structure. The primary structure is the simplest of all the structures. When all the hydrogen bonds are disrupted, the secondary, tertiary and the quaternary structures gets disrupted, which leads the protein to the most simplest structural form, that is the primary structure. In this structure, the a carbon atom is bonded to hydrogen atom, carboxyl group, amino group, and an 'R' group.