5. Randy's scenoe teacher is giving a demonstration to show how a metal reacts with different acids. He places a small piece of the metal in each of three beakers containing a solutions of three different
acids. He adds a plece of the metal to a fourth beaker that contains only water. What is the purpose of
the fourth beaker? 13.N.1.1)
A It ensures that the hypothesis will be correct.
B. It provides more data to include in a lab report.
C. It adds an Independent variable to the experiment.
D. It is the control and serves as the basis for comparison.

Beryl states that insulation with the smallest possible thermal conductivity is best to keep a house warm in winter, but worst for keeping a house cool in summer. sapphire insists the reverse is true: low thermal conductivity is good in the summer, but bad in the winter. which one, if either is correct? a. beryl, because low thermal conductivity results in low heat transfer. b. beryl, because low thermal conductivity results in high heat transfer. d. sapphire, because low thermal conductivity results in high heat transfer. e. neither, because low heat transfer is desirable both in summer and in winter.