Which system warns a person that the soup is to hot drink?

There's no single system that warns a person about hot soup. It's a combination of things:

* Your senses:

* Sight: The soup will look steaming and bubbly, indicating it's hot.

* Touch: If you carefully touch the bowl, you'll feel the heat radiating from it.

* Smell: Hot soup often releases a strong aroma.

* Your experience: You know from past experience that soup can burn you if it's too hot.

* Cautionary words: Someone may warn you that the soup is hot.

So, it's a combination of sensory input, learned knowledge, and sometimes the kindness of others that helps you avoid burning yourself on hot soup!