Instructions: select all the correct answers.
which of these descriptions defines general characteristics of a symbol?

symbols are subtle and intangible thoughts or details.

symbols have a concrete, physical existence.

symbols carry alternate, associated meanings.

symbols are always explicitly stated in the text.

The correct answers are: 

Symbols are subtle and intangible thoughts or details. 
Symbols have concrete, physical existence.
Symbols carry alternate, associated meanings.

Symbols could be intangible, but it could also be existing physically so both applies. It is something we associate with an object, person, or idea.

The correct answers are Symbols have a concrete, physical existence. Symbols carry alternate, associated meanings.

Indeed, the definition of a symbol is a visual sign or an image that represent an idea, notion, person, place or concept.

Letters and numbers are symbols and images, sculptures and other forms of art are also symbols and thus have a concrete physical existence. They carry alternate associated meanings. The American Bald Eagle is normally a carrion eating bird but it has become the symbol of the United States.

C. I and III