Anchor: Adequate DO is maintained by replacing the air above the water in the bags with oxygen from a compressed gas cylinder, and sealing the bags or by use of an airstone supplied by a portable pump.
Entailed: Adequate DO replaces the air with oxygen.
Contradiction: Adequate DO replaces the air with water.
Contradiction: The shirt is white.
Contradiction: There is a chance that cars might pass illegally.
Contradiction: These costs change constantly and can't be captured.
Contradiction: They don't involve checks anymore, at least for me.