I would think its B but im not positive
Answer: DNA
Explanation:
The chemical subunits that make up Deoxyribonucleic Acid and that form the genetic alphabet are called DNA
The molecules will continue to move across the membrane in both directions
Hope this helps! ;)
I think its pulmonary circulation too.
Stratosphere
The ozone layer protects life on earth by absorbing harmful ultraviolet radiation. The ozone layer is located between seventeen kilometers and thirty-five kilometers above the earth's surface in the stratosphere (2). The ozone layer is also known as the earth's shield. This layer contains high concentrations of ozone. It is interesting to note that Ozone is made up of three oxygen molecules; water consists of one hydrogen molecule and two oxygen molecules. It absorbs about ninety-seven percent of the sun's ultraviolet rays.