Which substances interfere with oxygenation of tissues and cause suffocation?

• A. Substances that cause tissue oxygen deprivation by chemical action
• B. Substances that interfere with oxygenation of tissues and cause suffocation
• C. Substances that taste bitter
• D. Substances that neutralize acids

Answer: (B)

Oxygen delivery to tissues can be blocked or impaired by agents whose main effect is preventing oxygen from reaching or being used by cells, leading to suffocation. These substances—asphyxiants—disrupt any step that ensures oxygen gets to tissues: they can displace or dilute oxygen in the environment, bind or interfere with hemoglobin so oxygen transport drops, or block cellular respiration so cells can’t use the oxygen that arrives. That description matches the idea of substances that interfere with oxygenation and cause suffocation, which is why it’s the best choice. The other descriptions describe effects that aren’t about stopping oxygen from reaching or being used by tissues (for example, a chemical action without the specific suffocation mechanism, a taste cue, or neutralizing acids), so they don’t capture the intended concept as directly.