Answer:
If there are no plants in the tank, they will run out of oxygen because there is nothing producing oxygen.
Explanation:
Darwin discovered that the lizards on the island were able to adapt an ability to swim and dive in their habitat for food to survive. Species that did not have those same adaptations could not survive. This relates to natural selection because one species of organisms better adapted to their environment and tended to survive and produce more offspring.
They probably fall into the bacteria catagory
