What type of materials should never be flushed down a toilet?

Flushing the wrong materials down a toilet can lead to severe plumbing issues and damage to septic systems. The correct answer emphasizes that chemicals, grease, wipes, and non-biodegradable items should never be flushed.

Chemicals can disrupt the balance of bacteria that are crucial for breaking down waste in septic systems. Grease can congeal in pipes, creating blockages that are difficult and expensive to clear. Wipes, even those labeled "flushable," often do not break down like toilet paper and can accumulate, leading to clogs. Non-biodegradable items, such as plastics, can cause significant harm to the sewage system and the environment.

The other options include items that, while problematic, do not encompass the broader range of hazards posed by the items listed in the correct answer. For instance, while food scraps and garden waste or hair and dental floss can lead to issues if flushed, they are not as universally harmful as the serious chemical or structural impacts of flushing wipes or grease. Thus, focusing on the complete range of hazardous materials reinforces proper septic system maintenance and environmental responsibility.