According to NASA’s scale bar and anatomy, many large lymph node
remains have been discovered by Phoenix Lander on Mars.
Fig. 1 below links to a Phoenix photo labeled with lymph node remains
of 8,500 microns and 17,000 microns in their long diameters. Their
sizes suggest those remains could be those of humans, as human lymph
nodes range from 1,000 microns to 20,000 microns in diameter (Ref.
1).