physical-object
public top level
- article 1
- artifact 2187
- body-part 106
- cell 134
- chart 4
- chemical-group 4
- cloning-vector 1
- commodity 204
- fossil 6
- gene 25
- geological-formation 86
- land 54
- letter 1
- natural-depression 43
- natural-object 505
- obstacle 3
- organism 584
- photograph 1
- piece 9
- seashore 4
- section 1
- slope 17
- antigenic-determinant
- beach
- bubble
- charm
- cotton-fiber
- freckle
- marsh
- meniscus
- pathological-plaque
- permafrost
- scablands
- space-debris