Which steps are required to determine the actual width of a xylem vessel seen in transverse section with a \times40 objective lens? 1 Change mm to µm by multiplying by $10^{-3}$. 2 Use a stage micrometer with the \times10 objective lens to calibrate the eyepiece graticule. 3 Use an eyepiece graticule to measure the width of the xylem vessel. 4 Multiply the calibration of the eyepiece graticule by the number of eyepiece graticule units.
- A1, 2, 3 and 4
- B2, 3 and 4 only
- C1 and 2 only
- D3 and 4 only