Final answer:
Theropod footprints are characterized by claw impressions and generally lack heel impressions, distinguishing them from the flat-footed ornithopod footprints. The correct option is A. claw, heel
Step-by-step explanation:
The student's question pertains to the characteristics of theropod footprints compared to those of ornithopods. Unlike ornithopods, theropods had footprints that included distinct claw impressions and typically lacked heel impressions. Theropods were bipedal dinosaurs, and their footprints often show the three primary toes with sharp claw tips, reflecting their life as active predators.
The presence of claw impressions instead of flat nails is a notable feature in these footprints. However, theropod footprints usually do not clearly show impressions made by a heel or ankle, unlike the more flat-footed ornithopods, which could leave such marks. The correct option is A. claw, heel