Scientists can tell this by looking at seismic waves released by earthquakes. ( if you need me to elaborate more ask)
B- lack of control.
the scientists did not have a proper control group.
Magnetic fields are areas where an object exhibits a magnetic influence. The fields affect neighboring objects along things called magnetic field lines. A magnetic object can attract or push away another magnetic object. You also need to remember that magnetic forces are NOT related to gravity. The amount of gravity is based on an object's mass, while magnetic strength is based on the material that the object is made of.
Answer:
3MgCl2 has 9 atoms.
Explanation:
The Element Magnesium (Mg) has 3 atoms.
The Element Chloride (Cl) has 6 attoms.
Their fore 6 + 3 is 9 of course. 3MgCl2 has 9 atoms.
BTW: 3MgCl2 is a molecular compound as well as H2O and CO2.