Which term best indicates the total number of neutrons and protons in a particular isotope of an element?     atomic number    mass number     group number    atomic mass

Mass number.

The atomic number just describes the number of protons, the group number identifies which column of a standard periodic table an element can be found in, and the atomic mass is just the mass of the atom.

Sun is explosive itself spread 9 planets.earth is 3rd explosive in the solar system about 500 hundred million years ago . first earth became ice age and freezing climate.centre of earth magma. north zone is artic . south is anatric

Change in speed or direction : )