While packing equipment for a field study, dr.
mokembe was trying to determine if he needed to
include both a dissecting and a compound
microscope. in which case would a scientist choose
to use a dissecting microscope rather than a
compound microscope?

The type of object to be observed determines whether dissecting microscope or compound microscope should be used.

Explanation:

A dissecting microscope is usually used to observe the surface features of a specimen and compound microscope is used for an in-depth observation of the specimen.

The magnification of dissecting microscope is less than the magnification of compound microscope but dissecting microscope gives a three dimensional image of the specimen. Another special feature of dissecting microscope is its long working distance.

Dissecting microscope uses the reflected light and thus preparation of specimen is usually not required. These features and its long working distance makes dissecting microscope an excellent tool in forensic and scientific applications.  

Compound microscope can be used in situations when a high magnification is required. Looking through the specimen is possible by the use of compound microscope.  

Thus the type of specimen and in how much detail it should be examined determines the type of microscope chosen.

allowed for the prediction of the properties of missing elements.

this is more of a statement than a question. is there answers to go along with this, or is it opinion based?