In the early days of antibiotic use , penicillin and sulfonamide were used to successfully treat a variety of bacterial infections . in later years stronger antibiotics were needed because some bacteria were either resistant to or not affected by these same antibiotics . this situation is best explained ?

(asap! big points! ) an unknown substance is heated from 10 °c to 25 °c. the table below shows the state of the substance at different temperatures. first row: time (minutes) second row: temperature of liquid (degrees celsius) third row: state of matter 0 10 solid 2 15 solid 4 17 6 17 8 17 10 23 liquid 12 25 liquid which statement is correct about the unknown substance? a. its melting point is 17 °c. b. its melting point is 15 °c. c. the substance sublimes at 15 °c. d. the substance exists as a gas at 17 °c.