This ecosystem model shows how disease impacts everyone. There are 4 different species: the grass, rabbits, foxes, and mountain lions. Each species is in a different tropic level. The grass is the primary producer, the rabbits are the herbivorous consumers, the foxes are the 1st level carnivorous consumers, and the mountain lions are the 2nd level carnivorous consumers. The grass is green, the rabbits are black, the foxes are yellow, the mountain lions are red. A limiting factor in my ecosystem is disease, which will kill more species in every tropic level. The user is able to change the amount of disease infectivity by using the slider. The organisms that are red means that they have been infected by the disease, and some of the infected may survive, some may die. You can only change the initial amount of rabbits, but you are able to click the "add fox" and "add mountain lion" button to add more predators as the model runs on. You can change the amount of energy for the rabbits, foxes, and mountain lions needed to reproduce by using the sliders. The sprouting rate is the amount of grass that is reproduced, so the higher the sprouting rate, the more grass there will be. Unfortunately, you cannot use sliders to control the birth and death rates but they are shown in the graph, where you can see the population of each species over time. Some things that could improve my model is list the number of infected species there are, but I knew that it would be very complicated so I thought that just giving out the amount of each species would be good enough. Also the clock seems to be broken, and I tried multiple times to fix it, but it still doesn't work. Nevertheless, the model works fine even though the clock may not work. Another thing that I could improve on is fixing the lag in the model, but there is so much going on in the code that I don't know where to fix it. Anyways, hope you like it :)