Photosynthesis - urgent help!

[ren347]

I am doin an experiment where there are two plants in test tubes in water which contains phenol red. The experiment is to find out if plants absorb carbon. What are the independent, dependent and control variables?

[Moonbear]

You need to provide some of your own work first. How do you define (or what are the differences between) an independent, dependent, and control variable?

Can you list all the variables in your experiment, even if you aren't sure which kind they are yet? Otherwise, you have not yet provided enough information for us to help you.