Answer:
Yes, a biologist looking through a microscope can usually tell whether she is looking at a single microtubule or at two microtubules lying side by side.
Step-by-step explanation:
Microtubules are cylindrical structures that form part of the cytoskeleton of cells. They have a distinct appearance under a microscope, appearing as long, thin, tubular structures. When two microtubules are lying side by side, they will usually appear as two distinct tubular structures, with a small gap between them.
By adjusting the focus and angle of the microscope, the biologist can usually get a clearer view of the microtubules and determine whether they are single or double. Additionally, different microtubule staining techniques can be used to help visualize individual microtubules and distinguish them from each other.
However, there may be cases where it is difficult to determine whether two microtubules are lying side by side or whether they are part of a larger structure. In these cases, additional imaging techniques, such as electron microscopy or super-resolution microscopy, may be necessary to provide a more detailed view of the microtubules.