1. which sequence shows the transfer of oxygen for use by the body? a, air, lungs, blood, cells, cellular respiration b, cellular respiration, blood, lungs, air c, food, digestive tract, cells, cellular respiration d, air, lungs, digestive tract, cellular respiration

A

Explanation:

Air enters the lungs from the atmosphere and through the airwaves (trachea and bronchioles). When it gets to the lungs, air exchange occurs in the capillaries with oxygen getting into the blood while carbon dioxide gets out. This exchange is based on diffusion gradients. The blood transports the dissolved oxygen to the tissues and cells and is also taken up by diffusion. The oxygen is then used as a proton acceptor in cellular respiration in the Krebs cycle.  

the backbone of the dna and rna compound is sugar phosphate.