Question

when are \ser\ and \estar\ used?
\ser\ is for physical characteristics. \estar\ is for location.
both of them are used interchangeably.
\estar\ is for physical characteristics. \ser\ is used for emotions.

Explanation:

"Ser" is used for inherent, permanent traits like physical characteristics, while "estar" is used for temporary states and locations. The first option correctly matches core uses, the second is wrong as they are not interchangeable, and the third reverses/incorrectly assigns their uses.

Answer:

"Ser" is for physical characteristics. "Estar" is for location.