The picture is a scientific model which is used to explain the concept of the water cycle by means of pictures and descriptions.
<h3>What is a scientific model?</h3>
A scientific model is a representation which may be in form of pictures, illustrations, objects, or ideas which are used to explain a particular concept by scientists.
Scientific models are usually employed to explain either difficult to understand concepts or scarcely observable phenomena in order to enrich the knowledge and comprehension of others.
The given illustration is an example of a scientific model. It is used to explain the concept of the water cycle. By means of pictures and descriptions, the various processes of the water cycle can be fully comprehended.
Also, by means of a cyclical illustration, the model helps to explain that the water cycle is a continuous repetitive process.
In conclusion, scientific models may be in form of pictures, illustrations or objects.
Learn more about scientific models at: brainly.com/question/18603376
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<h2>The given statement is true</h2>
Explanation:
Iron absorption occurs in the duodenum and upper jejunum of small intestine
- At physiological pH ferrous iron is rapidly oxidized to the insoluble ferric form 
- Gastric acid lowers the pH in the duodenum which enhances the solubility and uptake of ferric iron
- Once iron gets inside the enterocyte it can be stored as ferritin;Ferritin is a hollow spherical protein which helps in storage and regulation of iron levels within the body
- Ferritin molecule have ferroxidase activity which helps in the mobility of Fe2+ out of the enterocyte by ferroportin 
- Transferrin is the major iron transport protein which transports iron through blood
- Fe3+ binds to transferrin so Fe2+ transported through ferroportin must be oxidized to Fe3+
- Fe2+ needs to be oxidized first so that it can be transported through ferroportin
- Once iron gets inside the cell it can be used for various cellular processes
 
        
        
        
The barnacles are only able to attach them selfs to surfaces in the water. Since the surface is limited, barnacles are attaching themselves to the other barnacles, crowding the rock. The muscles were not able to grow or attach themselves off the surface of the rock. Same thing with the mussels that are growing on the rock. So not only barnacles are crowding the rock, but Mussels as well are crowding the rock.