Which would be the best insulator

A. diamond
B. gold
C. lead
D. concrete

Iknow the answer to 13 is b and 14 is d. i just need to know why the correct answers are correct

Which of the following statements is true about planck’s law

Margaret wants to make an orange flavored drink by stirring powdered drink mix into a glass of water. she doesn't like drinks that have small clumps of powdered solid in them, so she wants the drink to be a perfect solution. what factors should margaret not consider when deciding how much powder to add to her glass of water?