- At least 2 Stomach cards adjacent in the Tract must have Bacteria of the depicted type.
- At least 3 Stomach cards in the Tract must have Bacteria of the same type (any type will do).
- The first and last Stomach card in the Tract must have Bacteria of the same type (any type will do).
- At least 2 Stomach cards in the Tract must have the X feature (Crystal, Tool, or Bacteria type).
- Stomach cards with all 4 Bacteria types must be present in the Tract.