Ethylene gas is best described as

• A. A colorless, odorless hydrocarbon produced naturally by some fruits and vegetables
• B. A pungent toxic gas produced by spoiled meat
• C. A colored liquid used in food processing
• D. A sweet-smelling essential oil used for flavoring

Answer: (A)

Ethylene is a gaseous plant hormone that regulates fruit ripening. It’s a small hydrocarbon (C2H4) produced naturally by many fruits and vegetables as they mature, and it is typically colorless and odorless, so it isn’t detected by sight or smell. This quality helps explain why it plays a signaling role in ripening without being noticed directly, and it explains why it’s described as a gas produced by produce. The other options describe uses or properties that don’t match ethylene—it's not a pungent toxic gas from spoiled meat, not a colored liquid used in processing, and not a sweet-smelling essential oil. In practice, controlling exposure to this gas after harvest can either slow or hasten ripening, depending on the desired shelf life and market timing.