1 Earth's continents are constantly in motion because they sit on top of gigantic plates which float on Earth's mantle.
Energy from the Earth's core creates convection currents in the molten layer, and the currents move the plates. Over
extremely long periods of time, this movement creates new
biomes
b plates
C. atmospheric layers
d. elements
a.

212121212121212122121212121121212122121212121212121212121n i think

answersilicon (si); oxygen (o);

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.

explanation:

a