Which of the following is a sign of poor quality water? a. zero turbidity b. a ph of 7.0 c. high phosphate content d. high dissolved oxygen

 c. High phosphate content

Zero turbidity means that the water is clear. A clear water indicates that the amount of substance dissolved is less and the water is purer than the murky one. A good pH would be neutral pH of 7. High dissolved oxygen allow fish and another organism to grow.
Phosphate content is beneficial to plant but in high level, it can cause eutrophication, makes the oxygen level decreased and other problems. 

The sample with the lowest specific heat capacity will have the greatest temperature increase. in this case, it would be platinum.