Use the graph above to answer the following question. this graph shows the population trends of five populations over time. which statement is the best explanation for the changes in population e?

a. the decline in b and d reduced the competition for resources resulting in an increase in species e.

b. individuals of species e immigrated into this habitat from the surrounding areas

c. species e started eating species a because the increase in e occurs concurrently with the decrease in a

d. species c moved into the niche previously occupied by species b resulting in an increase in species e

The best explanation is provided by statement A.

Competition exists between organisms that occupy the same trophic levels in a food chain. The competition is due to the fact that there is a limited number of resources available to the organisms in their habitat. It is likely that organisms B and D were competing for resources such as food and space with organism E; when B and D declined in numbers, organism E had an easier access to resources and so its population increased. 

The simplest and most helpful visual aid for this experiment would be if the student sets rulers of some sort or maybe pieces of wood that are properly marked with certain measuring unite. If they are set right next to each plant, the student will be able to monitor constantly how are the plants growing, and the smaller the measuring unites the better, as the student will be able to monitor the situation in higher detail.

Over time, the plants will most surely develop differently, so the student will have it easier to notice the changes. Considering that it is an experiment in question, the student should use proper measurements and to be able to have detailed numbers for it.