is bladderwort a producer of a consumer. An animal that can't produce its own food and it eats plants and other animals. That is what a consumer is.
If it is; What is the purpose of a control in verifying a hypothesis or conducting an experiment, it is: Controls are needed to eliminate alternate explanations of experimental results. That is in order to test a particular variable you need a control. For e.g.
From RationalWiki. An experimental control, often referred to as a control group, is a population or set of objects that is statistically similar to the set being tested, on which no changes are implemented. In psychology and biology, the control group is very important, since results are often statistical rather than concrete. For instance, in testing a drug for a malady, some percentage of the test subjects will heal with no intervention (or heal at some rate in a third group, people getting an existing remedy).