The highest point the medium rises to and a trough is the lowest point the medium sinks to.
Carbon dioxide in the tissues is produced as the result of oxidation of glucose...
This carbon dioxide in process of respiration diffuse out of the tissues in form of molecular carbon dioxide and join with water forming carbonic acid ...
In lungs again carbon dioxide is separated and released out of the body...
3D models are better than diagrams cause a diagram is flat, and its on a piece of paper, on the other hand 3D models have 3 Dimensions which show the model in a different view, they are also sometimes on paper but you have a better view if the model which helps you get more information of the diagram.
Hope I helped ya!! And plz put it under the right subject next time. This should go under Math.
My favorite color is blue 143