They send warmer and colder temperatures to different places (I may be wrong so you should just pick the answer above mine)
A Halogen is a group (or a column) on the periodic table. It contains fluorine, chlorine, bromine, and astatine!
The answer is C. the carbon symbol C with one dot on each
the top, bottom, left, and right sides
Answer: the amount of force on the spring scale
Explanation:
Well a question to ask would be if the mass of the material has changed significantly as that would determine that the substance is radioactive or if there have been any high readings found by a Geiger meter in certain period of time
hope that helps