Carlotta adds too much salt to her soup. She recalls that evaporation can be used to separate salt from salt water, so she plans to leave the soup on the stove on low heat until the soup is less salty.

When soup simmers, some of its water evaporates, but dissolved salt does not evaporate with the water. As water leaves, the same amount of salt is concentrated in less liquid, so the soup becomes saltier. Therefore, the correct choice is A: the soup will become saltier because evaporation removes water and leaves the salt behind.

AI-written and checked against the verified answer.