Calculating actual cell structure length from micrograph using magnification Steps:

• Measure the image length of the cell structure on the electron micrograph in millimeters (step 1).
• Convert the measured length to micrometers if needed, but here step 4 adjusts for scale.
• Apply the magnification factor by dividing the adjusted image length by the given magnification value.
• Compute actual length in μm using actual size = image size / magnification, incorporating unit adjustments. Why D is correct:
• Steps 4 and 5 apply the formula actual length (μm) = (image length / 1000) / 8, which scales the mm measurement to μm when magnification implies a factor of 8000x (1000 × 8). Why the others are wrong:
• A: No step 6 exists, making it invalid.
• B: Omits necessary unit scaling (divide by 1000), yielding incorrect μm conversion.
• C: Step 2 wrongly reduces length; no step 6 exists.

Final answer: D