Answer:
The three-point test
Explanation:
The three-point test refers to a ground test utilizing an auxiliary current electrode and an auxiliary potential electrode.
I believe this is a double replacement. As you can see none of the chemical symbols are missing, there just "replaced".
1) 1.8 micrograms(least)
2) 1.8 grams
3) 1.8 kilograms(greatest)
