Which steps are required to determine the actual width of a xylem vessel seen in transverse section with a $\times 10$ objective lens? 1 Change from mm to $\mu$m by multiplying by $10^3$. 2 Use a stage micrometer on a $\times 4$ objective lens to calibrate the eyepiece graticule. 3 Use an eyepiece graticule to measure the width of the xylem vessel. 4 Multiply the number of eyepiece graticule units by the eyepiece graticule calibration.
- A1, 2, 3 and 4
- B1 and 2 only
- C2, 3 and 4 only
- D3 and 4 only