When using your sputnikis blue-ringed lens the diameter of

Question

Your Sputniki has two (2) Objective Lenses, one with a Yellow Ring and the other with a Blue Ring.

Your Sputniki has an Ocular Micrometer (Golly!). It is marked from 0 through 100 Ocular Units. You snaffle one of our MIC 101 Stage Micrometers to calibrate your Sputniki!s Ocular Micrometer. Using the Blue-Ringed Lens you find that approximately 75 Ocular Micrometer Units span 100 μm on our MIC 101 Stage Micrometers.

When using your Sputniki!s Blue-Ringed Lens, the Diameter of the Heterocyst of the Cyanobacterium Nostoc sp. measures a bit more than 2 (two) Ocular Units. Approximately how large is the Heterocyst of a Nostoc?

1. Approximately 1.25 μm.
2. Approximately 2.5 μm.
3. Approximately 7.0 μm.
4. Approximately 9.0 μm.