Use the information provided to explain the relationship between IAA concentration, cell wall plasticity and mean growth of the stem segments.

Use Figure 6 to calculate the percentage increase in mean growth of the stem segments when the IAA concentration was increased from 10–8 mol dm–3 to 10–5 mol dm–3

Give your answer to 2 significant figures.

Show your working.

Answer ______________ %

A technician produced the different concentrations of GA solution from a stock 10–1 mol dm–3 concentration of GA.

Describe how the technician produced the 10–3 mol dm–3 solution.

Describe a suitable procedure the student could follow to investigate the effect of different concentrations of GA on the growth of stem segments.

In your answer, you should include the variables that should be controlled in this investigation.