Which of the following is true about antifreeze?

Antifreeze is primarily composed of substances such as ethylene glycol or propylene glycol, which are toxic to humans and animals. When ingested, antifreeze can lead to serious health issues or even death due to its toxic properties. This toxicity is why antifreeze must be handled with care and stored securely, as accidental ingestion can happen, particularly with children or pets who may be attracted to its sweet taste.

Understanding the nature of antifreeze is crucial for safe vehicle maintenance and environmental awareness, as improper disposal can harm wildlife and water sources. The other choices do not accurately reflect the properties of antifreeze: it is neither safe for ingestion nor an essential nutrient, and while some chemicals may break down in the environment, antifreeze is not biodegradable in a way that can eliminate its harmful effects.