Final answer:
The oral mucosa is the best place to check for petechiae in dark-skinned individuals, with palms and soles being other potential areas for observation.
Step-by-step explanation:
The best place to observe for the presence of petechiae in dark-skinned individuals is the oral mucosa. This is due to the contrast in color, making the petechiae more visible against the lighter background of the mucosal tissue. In addition to the oral mucosa, other locations such as the palms and soles can also be examined for petechiae, as these areas may exhibit signs that are easier to detect than on the darker skin of the face or buttocks.