An experiment was designed to determine whether or not ultraviolet light affected the growth of lichens. two groups of lichens were grown under identical conditions, in visible light, except one group of lichens was also exposed to uv light while the other was not. in this experiment the group of lichens grown in visible light without uv light is known as the a. control. b. hypothesis. c. dependent variable. d. limiting factor.

The correct answer is option A, that is, control.

A controlled variable refers to something, which is maintained constant all through the experiment. However, in various experiments, one must also require a control. This is distinct from a controlled variable. A control is something, which is used as a standard of comparison for examining the results of an experiment.  

the menstrual cycle – higher tier. negative feedback mechanisms affect the production of hormones in the menstrual cycle. oestrogen also stimulates the release of lh (luteinising hormone) from the pituitary gland, which in turn controls the production of progesterone.

golgi body just took the test on edge