So here we have an example problem that says to complete the phosphorus cycle diagram down below right here by matching the following terms in this word bank to the correct number in the diagram. It says that not all answer options will be used. Recall from our last lesson video that the largest reservoir of phosphorus are phosphorus-containing rocks. It makes sense to start this diagram off here with number 1 with those phosphorus-containing rocks. That is going to be the word that goes into that position.

So for number 1 down below, we can put in 'rock' and then we can cross off 'rock' from the list above. Now, we know that the process of weathering can release the phosphates from those phosphate-containing rocks. So, number 2 here is going to be 'weathering', and we can go ahead and fill in 'weathering' into number 2 down below. Then we can cross off 'weathering' from the list in the word bank. Once the phosphates have been released through weathering, they can make their way into the soil and into freshwater.

From there, the phosphates can be assimilated into organisms, into biomass. Notice that we can return the phosphates back to soil and freshwater from the biomass through the process of decomposition. So this next arrow, number 3, is going to be 'decomposition', allowing the phosphates to return from the biomass back to the soil and or the freshwater. We can go ahead and put 'decomposition' here for number 3 and then cross it off the list from above. As you can see, from the freshwater, the phosphates can run off and end up in the ocean.

So number 4 here is going to be 'ocean', and we can go ahead and fill that in down below. Once the phosphates are in the ocean, then they can begin to sediment back into the rocks. That returns us back to number 1, which again is the 'rock'. This here completes this example problem, and I'll see you all in our next video.