The most important thing is to try and extinguish a fire if a fire extinguisher is near. If not, they second most important thing is to rush out of the lab using the fire escape route and call the local fire department which will then handle the situation.
I have encountered this question before, and the given diagram shows no producers. Moreover, it consists of pictures of five organisms, with no relationship being shown between them. Therefore, in order to make the model more accurate, Maria should add B. The sun and arrows to show the flow of energy.
Answer: B-cells fight bacteria and viruses by making y-shaped proteins called antibodies, which are specific to each pathogen and are able to lock onto the surface of an invading cell and mark it for destruction by other immune cells. C-cells are a virus-bound antibody that binds to receptors, on the surface of phagocytic cells and triggers a mechanism known as phagocytosis, by which the cell engulfs and destroys the virus.
Explanation: sorry this answer was not simple at all -_-