If you use more than one independent variable at a time, and will observe a change, you will not know which variable contributed to a changed result.
Derived characteristics refers to those traits that have changed from ancestral form or function. The derived character, which cause K. monera to be divided into K. archeabacteria and K. eubacteria is that genetically and biochemically the two are different. The archeabacterial possess unusual lipid, which is not find in eubacteria or any other organism. And this give it the capacity to live in extreme environments.
Yes. They are aquatic animals.