Each graph shows the population size over time for two different organisms. what relationship most likely exists between the two organisms in each graph? predator and prey obligate mutualism obligate parasitism

I Graph - obligate  mutualism

II Graph - obligate  parasitism

III Graph - predator  and prey

Explanation:

In the first graph, the relationship between ant and the acacia tree is mutualism which means that both the species provide some form of benefit to each other.  

The tree provides food and accommodation to the ants and in favor to that the ants protect the trees from herbivores.  

In the second graph, sea crab gets food from the sea urchin. The crab usually sticks to the urchin and only harms it.

In the third graph, grasshopper prey upon the grass hence they have a predator and prey relationship

answer; i believe the correct answer to the above question is ( friction)