A scientist finds a fossil that she thinks might make a good index fossil.
Which characteristic does this fossil most likely have?
O It is the remains of an organism still found alive today.
O It is the remains of an organism that is found in abundance nearby.
O It is the only fossil for this type of organism that has ever been found.
O It is the remains of an organism that lived in a narrow geographic area.

i believe it is c hope u do well on ur test good luck have a good day pls mark brainliest

atomic mass = 39

number of neutrons = 20

number of protons= 19

electronic configuration = 1s2 2s2 2p6 3s2 3p6 4s1

the number of electron in first shell = 2

number of electrons in n=3 shell = 8

considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.