Answer is the first option Place a metal paper clip on a table and slowly bring each electromagnet closer to the paper clip to see which can attract the paper clip from a greater distance.
I don't know why but I find your questions a bit too easy..
Asbestos, tobacco smoke, and formaldehyde are a few common examples
Number 6 is D, However Number 7 is not humus. They are contributing to the formation of silt. Which is kind of like a fertilizer.
