Final answer:
The appropriate unit of length to measure a typical plant or animal cell is micrometers (d), as these cells range from 10 to 100 micrometers in size.
Step-by-step explanation:
The unit of length you would generally use to measure a typical plant or animal cell is micrometers (d). To give you a perspective, it is mentioned that a typical human red blood cell is about eight micrometers in diameter, which is a size that requires a light microscope to be viewed. Since a typical plant or animal cell ranges from approximately 10 to 100 micrometers in size, micrometers are the most suitable unit of measurement for these cells, which are microscopic in scale. Centimeters and millimeters are too large to accurately represent the dimensions of most cells, and nanometers would be suitable for objects like viruses that are smaller than cells.