Resistivity measurements on the leaves of corn plants are a good way to assess stress and overall health. The leaf of a corn plant has a resistance of 1.8MOhms measured between two electrodes placed 20 cm apart along the leaf. The leaf has a width of 2.4cm and is 0.20cm thick.
1. What is the resistivity of the leaf tissue? Express your answer to two significant figures and include the appropriate units.