Which statement describes the Mercalli scale? This scale measures seismic waves based on their size.
This scale rates an earthquake according to how much damage it causes.
This scale produces a single rating for earthquakes that reach the surface.
This scale measures the magnitude of an earthquake based on the size of seismic waves.

Its B - "How much damage it causes"

Explanation:

i just got it right :)

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.