Question

Toxins like α-amanitin are used for research in much the same way as null mutants−to disrupt a process and see what happens when it no longer works. researchers examined the ability of α-amanitin to inhibit different rna polymerases. they purified rna polymerases i, ii, and iii from rat liver, incubated the enzymes with different concentrations of α-amanitin, and then tested their activity. the results of this experiment are shown below. these findings suggest that α-amanitin-treated cells will have reduced levels

Answer 1

The answer is reduced levels of mRNA synthesis. This is due to the fact that alpha-amanitin interferes with polymerase II that is involved in transcription of mRNA precursors.
The alpha-aminitin inhibits translocation of this polymerase from DNA after a transcription round. This therefore renders the enzyme unavailable for next transcription.
It also reduces the rate of translocation of the polymerase II along the DNA hence slows transcription.